•'••"••'-— 

m 


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MINING, 


AND  AR 


UNIVERSITYsrCALIFORNIA 


COLLEGE  of  MINING 
DEPARTMENTAL 
LIBRARY 


BEQUEST  OF 
SAMUELBENEDlCrCHRlSTY 


PROFESSOR  OF 

MINING  AND   METALLURGY 
1885-1914 


26.  MANUAL  OF  QUALITATIVE  CHEMICAL  ANALYSIS,     cy 
F.  BEILSTEIN.  Translated  by  "W  ILLIAM  RAMSAY,  D.Na.Sc. 


Extra  Volumes,  12mo,  cloth,  $1.12J| 

?B  APPLIED  MECHANICS.    By  HENRY  EVERS,  LL.D. 
15B  GENERAL  BIOLOGY.    By  T.C.  MACGINLEY. 


IN    COURSE    OF    PUBLICATION. 


ADVANCED     SCIENCE     SERIES. 

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Printed  uniformly  in  12mo,  averagim  350  pp..  fully  Illustrated,  doth 
e~<,m,  Price  $1.50  each  vol. 

1.  PRACTICAL  PLANE  AND  SOLID  GEOMETRY.  By  Professor 

F.  A.  BRADLEY,  London. 

2.  MACHINE    CONSTRUCTION    AND    DRAWING.       By   E. 

TOMKINS,  Liverpool. 

3.  BUILDING  CONSTRUCTION.    By  R.  S.  BURN,  C.E. 

4.  NAVAL  ARCHITECTURE-LAYING  OFF  AND  SHIPBUILDING. 

By  S.  J.  P.  THEARLE,  F.R.S.N.A.,  London. 

5.  PURE  MATHEMATICS.    By  E.  ATKINS,  Leicester.    2  vols. 

6.  THEORETICAL  MECHANICS.  By.  P.  GUTHRIE  TAIT,  Professor 

of  Natural  Philosophy,  Edinburgh. 

7.  APPLIED  MECHANICS.      By  Professor  0.  REYNOLDS. 

8.  ACOUSTICS,  LIGHT,  AND  HEAT.    By  W.  S.  DAVIS,  LL.D. 

9.  MAGNETISM  AND  ELECTRICITY.     By  F.  GUTHRIE,  B.A., 

Ph.D.,  Royal  School  of  Mines,  London. 

10.  INORGANIC  CHEMISTRY.  By  T.E.  THORPE,  Ph.D.,  F.R.S.E., 

Professor  of  Chemistry,  Glasgow.     2  vols. 

11.  ORGANIC  CHEMISTRY.    By  JAMES  DEW AR,  F.R.S.E.,  F.C.S., 

Lecturer  on  Chemistry,  Edinburgh. 

12.  GEOLOGY.  By  JOHN  YOUNG,  M.D.,  Professor  of  Natural  History, 

Glasgow  University. 

13.  MINERALOGY.     By  J.  H.  COLLINS,  F.G.S.,  Falmouth. 

14.  ANIMAL  PHYSIOLOGY.       By   J    CLELAND,    M.D.,  F.R.S., 

Professor  of  Anatomy  and  Physiology,  Galway. 

15.  ZOOLOGY.    By  E.  RAY  LANKESTER,  M.A.  (Oxon.),  London. 

16  VEGETABLE   ANATOMY  AND   PHYSIOLOGY.      By  J.  H. 
BALFOUR.  M.D.,  Edinburgh  University. 

17.  SYSTEMATIC  AND  ECONOMIC  BOTANY.  By  J.H.  BALFOUR, 
M.D.,  Edinburgh  University. 

19.  METALLURGY.  By  W.  H.  GREENWOOD,  A.  R.S.M.    2  vols. 

20.  NAVIGATION.    By  HENRY  EVERS,  LL.D.,  Plymouth. 

21.  NAUTICAL  ASTRONOMY.    BY  HENRY  EVERS,  LL.D. 

22.  STEAM  AND  THE  STEAM  ENGINE— LAND,  MARINE,  /:/;r> 

LOCOMOTIVE.    By  H.  EVERS,  LL.D.,  Plymouth. 

23.  PHYSICAL  GEOGRAPHY.    By  JOHN  YOUNG,  M.D.,  Professor 

of  Natural  History,  Glasgow  University. 


PRINCIPLES  OF  METAL  MINING. 


|ltttmim's   6I*mtntarti    Stunt*   Scries. 


PRINCIPLES 


METAL    MINING. 


BY 


J.    H.    COLLINS,    F.  G.S., 

AUTHOR  OF  A   "  HANDBOOK  TO  THE  MINERALOGY   OF  CORNWALL  AND  DEVON." 

"A  FIRST  BOOK  OF  MINERALOGY,"   ETC.  ; 
HONORARY  SECRETARY  TO  THE  MINERS'  ASSOCIATION  OF  CORNWALL  AND  DEVON,  ETC. 

JHiifc  76  Illustrations. 


NEW  YORK: 
G.    P.    PUTNAM'S   SONS, 

FOURTH.  AVENUE  AND  TWENTY-THIRD  STREET. 


PKEFACE. 


THE  art  of  mining  must,  to  a  large  extent,  be  learnt  at 
the  mine,  either  underground  or  at  the  surface.  The 
diligent  student,  however,  will  obtain  much  aid  from 
external  sources,  and  it  is  the  object  of  this  little  work 
to  convey  some  elementary  knowledge  of  the  principles 
and  facts  of  mining  in  a  form  suitable  for  the  instruction 
of  young  miners  starting  in  life — to  teach  them  what  to 
observe — and  how  to  interpret  their  observations. 

The  young  student  should  endeavour  to  add  to  his  own 
limited  experience  the  larger  experiences  of  many  men 
in  many  countries — by  reading  as  well  as  by  conversa- 
tion with  his  travelled  comrades.  He  should  also 
accustom  himself  to  make  written  notes  of  the  peculi- 
arities of  all  mineral  deposits  with  which  he  may  become 
acquainted,  and  of  the  cost  and  comparative  efficiency 
of  all  tools,  machinery,  and  materials  which  may  come 
under  his  notice. 

There  are  two  principles  universally  applicable  to  all 
legitimate  mining  operations:  First,  That  they  should 
not  be  unduly  injurious  or  dangerous  to  the  men  engaged; 

303303 


6  "PWEFACSE. 

second,  That  they  should  pay.  The  first  principle  has 
now  engaged  the  attention  of  the  Government;  as  to  the 
second,  it  behoves  all  honest  men  to  set  their  faces  against 
the  system  of  mining  with  a  view  to  the  interests  of 
stock-jobbers,  and  to  return  to  the  old  system  of  working 
a  mine  for  the  sake  of  the  ore  it  may  reasonably  be  sup- 
posed to  contain. 

I  am  now  preparing  a  larger  work  on  the  subject,  and 
shall  be  glad  to  be  informed  of  any  omissions,  errors,  or 
supposed  errors,  which  readers  of  this  little  work  may 
discover. 

J.  H.  C. 

TRURO,  August,  1874. 


CONTENTS, 


CHAPTER  I. 
INTRODUCTION,         ......         9 

CHAPTER  II. 
THE  GEOLOGY  OF  MINING  DISTRICTS,  .  .15 

CHAPTER  III. 
MINERALS  AND  ROCKS,       .....       20 

CHAPTER  IV. 

THE  NATURE  Off  MINERAL  VEINS,  •  *          .24 

CHAPTER   V. 
"HEAVES,"  ETC.,     .  .  •  .  .  .30 

CHAPTER  VI. 
DEAD  WORK  IN  VEIN  MINING,     *  .  .  »        34 

CHAPTER  VII. 
PRODUCTIVE  WORK  IN  VEIN  MINING,      *  »  .        43 

CHAPTER  VIIL 

THE  MINING  OF  BEDS  AND  IRREGULAR  DEPOSITS,          .       46 

CHAPTER  IX. 
ON  OPEN  WORKS  AND  HYDRAULIC  MINING,       .  .       54 


8  CONTENTS. 

CHAPTER  X. 

fAOB 

ON  THE  TOOLS  USED  IN  BREAKING  ROCK,  «          •       59 

CHAPTER  XI. 
ON  DEAD  WORK  IN  SHAFTS,  ETC.,  ...       65 

CHAPTER  XII. 
ON  THE  CONVEYANCE  AND  RAISING  OF  STUFF,    .  •       71 

CHAPTER  XIII, 
MACHINERY  FOR  RAISING  STUFF,  .  .  •  .79 

CHAPTER  XIV, 
THF,  DRAINAGE  OF  MINES,  .  ...       87 

CHAPTER  XV. 
ON  MACHINERY  FOR  WORKING  PUMPS,    .  .          •       94 

CHAPTER  XVI. 
ON  ORE-DRESSING  OPERATIONS,     •          .          •  106 

CHAPTER  XVIL 
ON  VENTILATION  AND  LIGHTING,  .  •          .          .      114 

EXAMINATION  QUESTIONS,  .  •          •          •  .125 

GLOSSARY,    .  .          .          •          •          •          .131 

INDEX,          ...  ...      146 


PBINCIPLE3  OF  METAL  MINING, 


CHAPTER    I. 

INTRODUCTION. 

1.  THE  art  of  mining  is  very  ancient,  and  eminently  pro- 
gressive; and  there  is  abundant  evidence  that  the  early 
miners  worked  with  very  rude  tools.  Cart  loads  of  stone 
hammers  have  been  found  in  the  old  workings  of  the 
Lake  Superior  Copper  Mines;  wooden  shovels  from  the 
ancient  Cornish  Tin  Stream  Works  may  be  seen  in  the 
museum  at  Truro;  and  the  rag  and  chain  pump  was  in 
use  in  some  of  the  Cornish  mines,  almost  within  the 
memory  of  men  now  living. 

Even  such  tools,  rude  as  they  seem  to  be  in  these  days 
of  gunpowder  and  steam  engines  indicate  a  consider- 
able amount  of  advancement — the  pump,  more  especially; 
the  rag  and  chain  pump,  with  all  its  imperfections,  was, 
no  doubt,  the  invention  of  some  man  of  abilities  very 
superior  to  those  of  his  neighbours;  and  probably  he  met 
with  much  opposition  from  the  men  who  were  in  the 
habit  of  lifting  the  water  out  of  their  shallow  pits  with 
large  shells  or  wooden  bowls. 

The  windlass  and  the  wheel-barrow  are  very  old  and 
very  simple  contrivances,  yet  their  introduction  is  even 
now  opposed  by  the  native  miners  of  Chili,  who  continue, 
as  did  their  ancestors,  to  carry  the  ore  to  the  surface  on 
their  backs,  mounting  the  "  stemples  "  which  are  driven 
into  the  wall  of  the  lode  to  serve  instead  of  ladders. 


10  PRINCIPLES   OF   METAL   MINING. 

The  use  of  gunpowder  for  blasting  in  hard  ground,  said 
to  have  been  first  used  in  the  parish  of  Breage  in  Corn- 
wall, is  scarcely  three  centuries  old;  and  even  yet  the 
ancient  mode  of  rendering  the  rock  brittle,  by  first  heat- 
ing it  by  means  of  a  fire  of  brushwood  kindled  in  the 
"  end,"  and  then  throwing  cold  water  upon  it,  is  still  in 
use  in  some  of  the  continental  mines. 

2.  These  facts  may  serve  to  illustrate  the  extreme  con- 
servatism of  the  race  of  miners;  a  conservatism  which 
has  induced  many  miners  to  look  with  dislike,  and  even 
with  contempt,  upon  every  kind  of  knowledge,  except 
that  which  may  be  learnt  in  the  mine  itself.     Such  pre- 
judices are  now,  however,  happily  passing  away,  and  the 
best  miners  are  beginning  to  see  that  the  study  of  various 
branches  of  science  may  not  only  accompany,  but  precede 
with  advantage,  actual  work  in  the  mine. 

Improvements  and  modes  of  working  have  now  become 
so  numerous,  that  all  their  details  can  scarcely  be  mas- 
tered by  any  one  man,  and  this  has  led  to  a  division  of 
labour  in  mining,  as  in  all  the  useful  arts.  The  different 
kinds  of  knowledge  bearing  upon  mining,  as  well  as  upon 
other  pursuits,  have  been  arranged  in  kindred  groups, 
called  sciences,  or  more  accurately  branches  of  science, 
each  of  which  it  would  be  the  labour  of  a  lifetime  to 
master  completely.  Yet  a  good  miner  should  be  acquainted 
with  the  rudiments  of  many  of  them,  as  he  will  be  sure 
frequently  to  see  advantageous  modes  of  applying  such 
elementary  knowledge,  and  he  will  thus  know  when  he 
should  call  in  the  special  aid  of  the  chemist,  geologist, 
mineralogist,  or  mechanic,  as  the  case  may  be. 

It  is  especially  important  that  every  miner  should  be 
acquainted  with  certain  primary  facts,  such  as  the  pro- 
perties of  matter,  the  laws  of  force,  the  relative  strength 
of  materials,  etc.,  and  such  elementary  knowledge  is  by 
no  means  difficult  to  acquire. 

3.  The  science  of  Mechanics  treats  of  the  action  of 
masses  of  matter  upon  each  other.    Hydraulics  is  simply 
the  mechanics  of  liquids;  Pneumatics,  the  mechanics  of 


INTRODUCTION.  11 

gases  and  vapours.  It  is  evident  that  in  mines  where 
masses  of  matter  are  always  being  moved,  and  which 
need  to  be  continually  freed  from  water  and  foul  air,  an 
elementary  knowledge,  at  least,  of  each  of  these  branches 
of  science  is  of  the  utmost  importance  to  all  engaged. 

In  metal  mines,  nothing  is  more  common  than  to  hear 
men  complaining  of  the  foul  air  in  a  bad  "end,"  and  with 
good  reason,  since  the  air  is  frequently  quite  poisonous. 
Yet  the  remedy  is  often  easy,  and  in  the  men's  own  hands. 
One  sees,  in  such  foul  ends,  the  ore  and  rubbish  allowed 
to  accumulate  behind  the  men  to  a  height  of  several  feet 
before  it  is  trammed  back  to  the  shaft,  so  shutting  up 
the  natural  path  of  the  fresh  and  pure  air.  The  miner, 
in  that  thoughtlessness  which  is  born  of  ignorance,  goes 
on  in  his  old  way;  the  captain,  sometimes  not  much 
better  instructed  than  the  men,  makes  no  remark,  and  so 
the  men  "  perish  for  lack  of  knowledge." 

Sometimes  one  meets  with  a  man,  who,  not  having 
studied  pneumatics,  has  yet  by  his  own  methods  of  close 
observation  learnt  the  lesson  which  that  science  would 
teach;  but  even  he  has  only  learnt  it  after  long  and  in- 
jurious experience.  Such  men  are  everywhere  rare,  but 
it  would  be  easy  to  teach  all  men  and  all  boys,  and  to 
impress  the  lesson  upon  their  minds  by  a  few  simple  ex- 
periments, that  the  cool,  pure  air  passes  into  the  end  on 
the  floor  of  the  level,  while  the  heated  impure  air  rises 
to  the  back  to  pass  out;  and  if  either  the  cool  or  the 
heated  currents  be  obstructed,  stagnation  will  be  the 
result.  This  subject  will  be  dealt  with  in  detail  in  the 
chapter  on  ventilation. 

4.  The  principle  which  underlies  the  great  majority  of 
ore-dressing  operations,  is  to  take  advantage  of  the  dif- 
ferent specific  gravities  of  the  ore  and  the  waste.  The 
same  principal  is  at  the  bottom  of  the  beautiful  art  of 
"  vanning."  It  ought  not  to  be  necessary  to  insist  upon  the 
great  value  of  this  art  to  the  metal  miner;  yet  it  is  truly 
astonishing  to  find  how  very  few  miners,  even  tin  miners, 
are  able  to  practice  it.  The  speed  and  accuracy  with  which 


12  PRINCIPLES   OF  METAL  MINING. 

\  , 

a  practised  vanner  determines  the  value  of  a  sample  of  tin 
ore,  fills  the  beholder  with  wonder  and  delight.  No  words 
can  describe  the  peculiar  motions  of  the  wrist  which 
serve  to  separate  the  ore  on  the  shovel  from  the  waste. 
The  only  way  to  learn  is  to  watch  closely  the  movements 
of  a  proficient,  and  to  try  to  imitate  him  as  closely  as 
possible. 

The  vanner  finds  by  experience  what  science  teaches 
from  pure  reasoning,  that  clean  water  is  essentially  neces- 
sary, if  the  results  are  to  be  accurate;  and  the  tin-dresser 
who  is  once  thoroughly  impressed  with  this  fact  will 
be  the  best  dresser;  because  he  will  see  the  importance 
of  securing  every  drop  of  this  requisite  which  comes 
within  his  reach. 

5.  The  science  of  Geology  should  be  known  in  its  broad 
outlines  to  all  miners,  especially  that  part  of  it  which 
treats  of  the  peculiar  deposits  of  metal  or  coal  ordinarily 
sought  for.  For  want  of  such  elementary  knowledge, 
many  important  facts  have  been  but  imperfectly  tinder- 
stood  by  the  miner.  Men  will  work  for  a  lifetime  in  a 
mine,  and  will  yet  be  totally  ignorant  of  the  peculiarities 
of  an  adjoining  mine,  not  to  speak  of  those  of  mines  in 
other  districts  or  in  foreign  countries.  How  few  Cornish 
mine  agents  even  have  ever  read  Mr.  Kenwood's  most 
valuable  works  on  the  metalliferous  deposits  of  their 
own  county,  published  thirty  years  ago !  How  few  ever 
commit  to  paper  their  observations  on  the  mines  in  which 
they  spend  their  lives !  In  the  absence  of  such  written 
notes,  facts  are  apt  to  fade  away  into  a  general  haze  in 
the  mind,  and  so  become  lost,  not  only  to  others,  but 
often  even  to  the  observer  himself. 

For  centuries  past  no  country  has  possessed  so  many 
good  mines,  or  produced  so  many  good  miners,  as  the  one 
little  county  of  Cornwall;  yet  the  mining  proverb,  "where 
it  is,  there  it  is,"  still  holds  its  own  in  the  county,  and 
will  continue  to  do  so  until  observations  are  multiplied 
and  intelligently  recorded  and  compared. 

The  phenomena  connected  with  bed  mining  are  much  less 


INTRODUCTION.  13 

obscure,  and  their  uncertainties  have  been  reduced,  per- 
haps, to  a  minimum;  but  costly  mistakes  have  frequently 
been  made,  which  might  have  been  avoided  by  the  appli- 
cation of  a  very  little  scientific  knowledge.  * 

We  may  reasonably  hope  that  a  brighter  future  is  at 
hand,  if  our  miners  be  supplied  with  what  is  really  known 
in  early  life.  Why  should  we  not  teach  a  lad  all  the 
little  that  is  certainly  known  of  the  laws  of  metalliferous 
deposition,  together  with  the  peculiarities  of  the  "  faults," 
"  troubles,"  heaves,"  etc.,  of  bed  and  vein  mining,  before 
sending  him  to  the  mine  at  all;  instead  of  allowing  him 
to  spend  his  life  in  painfully  acquiring  such  knowledge — 
the  A  B  C  of  mining — and  too  often  to  die  and  carry 
away  what  he  has  learnt,  leaving  his  brother  miners  none 
the  wiser? 

6.  Mineralogy  is  undoubtedly  a  science  of  great  import- 
ance to  all  practical  miners,  even  the  humblest.  Many 
miners  are  perfectly  alive  to  the  minute  points  of  differ- 
ence existing  between  the  different  minerals  ordinarily 
coming  under  their  notice,  although  they  have  usually 
picked  up  such  knowledge  hap-hazard.  Still,  stories  of 
valuable  minerals  having  been  thrown  away  in  ignorance 
of  their  true  value,  are  very  common  in  all  mining  dis- 
tricts, and  some,  at  least,  of  these  stories  have  been  proved 
to  be  true.  Even  in  such  a  tin-producing  county  as 
Cornwall,  large  and  valuable  lumps  of  "wood-tin"  and 
"toad's-eye"  tin  have  been  built  into  hedges,  and  fine 
lumps  of  silver  ore  were  found  a  few  years  since  built 
into  hedges  in  the  eastern  part  of  the  same  county.  No 
doubt,  indeed,  such  mistakes  have  occurred  within  the 
knowledge  of  most  miners. 

But  it  is  only  the  mistakes  which  have  been  discovered 
that  can  be  known;  it  is  very  probable  that  the  great 
majority  of  such  mistakes  are  never  found  out  at  all. 
The  only  safeguard  for  the  future  is  in  the  multiplication 
of  mineralogical  observers,  with  eyes  sharpened  by  prac- 
tice and  by  knowledge  to  discover  minute  points  of  differ- 
ence— men  accustomed  to  look  for  stones  of  strange  or 


14  PRINCIPLES   OP   METAL   MINING. 

peculiar  appearance,  and  in  the  habit  of  compelling  them 
to  give  an  account  of  themselves.  To  aid  such  men,  each 
mine  should  have  its  glass  case  filled  with  the  productions 
of  the  mine;  every  literary  institution,  in  a  mining  neigh- 
bourhood, should  have  its  collection  of  the  minerals  of 
the  district  nicely  labelled  and  catalogued ;  and  the  larger 
towns  should  try  to  get  illustrative  specimens  of  every 
mineral  substance  known,  to  serve  for  comparison  with 
any  peculiar  substance  which  might  be  discovered. 

7.  To  the  miner,  the  science  of  mineralogy  is  of  greater 
importance  than  that  of  Chemistry,  yet  it  naturally  leads  to 
an  elementary  knowledge  of  the  latter  science.  Here,  too, 
an  educated  may  have  over  an  untaught  miner  an  immense 
advantage,  by  simply  making  himself  acquainted  with  the 
operation  of  a  few  simple  tests,  and  especially  by  learning 
to  use  the  mouth-blowpipe.  To  be  able  to  make  an 
accurate  analysis  requires  months  of  study  and  years  of 
practice;  but  a  man  skilled  in  the  use  of  the  blowpipe 
will  often  be  able  to  determine  in  a  few  minutes  whether 
a  complete  analysis  is  desirable  or  not.  In  Cornwall 
many  miners  have  recently  acquired  this  very  valuable 
accomplishment,  in  a  sufficient  degree,  by  one  or  two 
winters'  practice  in  the  evening  science  classes  of  the 
Miners'  Association  of  Cornwall  and  Devon;  and  it  is 
much  to  be  desired  that  similar  classes  should  be  estab- 
lished in  every  mining  district  throughout  the  United 
Kingdom.  Of  course,  it  is  not  argued  that  these  different 
branches  of  science — mechanics,  geology,  mineralogy, 
chemistry — should  each  and  all  be  known  in  an  equal 
degree  by  all  engaged  in  mining,  or  that  all  together 
would  suffice  to  make  a  man  a  miner  without  practice  in 
the  mine.  It  is  simply  argued  that  a  good  engineman, 
and,  therefore,  also  a  bad  one,  will  be  the  better  for  a 
knowledge  of  the  properties  of  steam  and  the  chemistry 
of  the  furnace;  the  tributer  for  a  knowledge  of  geology  and 
mineralogy;  the  pitman  for  a  knowledge  of  the  relative 
strength  of  materials;  the  ore  dresser  for  the  elementary 
principles  of  hydrostatics ;  while  even  the  lander  at  the 


GEOLOGY   OF   MINING   DISTRICTS.  15 

shaft's  mouth,  and  the  boys  and  girls  who  "buck"  the 
ore,  will  be  the  better  for  a  little  elementary  knowledge 
of  mineralogy.  These  sciences  are  now  taught  in  the 
science  classes  in  connection  with  the  Department  of 
Science  and  Art  throughout  the  United  Kingdom,  and 
are  dealt  with  in  the  series  of  text-books,  of  which  this 
work  forms  one,  and  to  which  the  student  is  referred. 
A  brief  reference  to  the  special  bearings  of  the  sciences  of 
geology  and  mineralogy  upon  the  art  of  mining,  will  be 
given  in  the  next  three  chapters,  after  which  we  shall 
proceed  at  once  to  deal  with  the  more  technical  parts  of 
the  subject. 


CHAPTER  II. 

THE   GEOLOGY   OF   MINING   DISTRICTS. 

8.  The  Crust  of  the  Earth. — The  ground  upon  which 
we  tread,  as  deep  down  as  we  know  anything  about  it — 
is  often  spoken  of  as  the  "crust  of  the  earth."     The 
science  of  geology  teaches  us  what  this  crust  is,  and  that 
it  was  not  always  in  its  present  condition.     What  is 
now  dry  land  has  been  covered  with  the  waters  of  the 
sea  once,  or  many  times ;  while  the  sea  is  gradually  being 
filled  up  with  the  waste  of  the  land,  and,  at  the  same 
time,  portions  of  its  bottom  are  gradually  being  elevated 
by  forces  acting  from  below,  so  as  to  form  dry  land.    The 
study  of  these  various  changes,  both  past  and  present, 
belongs   to   the   science   of    geology,    more   particularly 
treated  of  in  the  text-book  of  that  science  published  in 
the  present  series,  to  which  the  student  is  referred  for 
more  detailed  information  than  can  be  here  given. 

9.  Classification  of  Rocks. — It  is  found  by  geologists 
that  the  various  rocks  which  go  to  form  the  so-called 
crust  of  the  earth,  may  be  primarily  divided  into  two 
great  groups,  called  stratified  and  unstratified. 


16  PRINCIPLES   OF   METAL   MINING. 

10.  Stratified  Rocks.— The  stratified  rocks  have  been 
mostly,  although  not  exclusively,  formed  by  the  agency 
of  water,  and  are  hence  called  aqueous.     They  form  mora 
or  less  regular  "  beds,"  often  extending,  with  but  little 
variation,  over  large  tracts  of  country,  and  resting  one 
upon  another  in  regular  order. 

11.  Unstratified  Rocks.— The  unstratified  or  igneous 
rocks,  as  they  are  frequently  termed,  on  the  contrary,  are 
much  less  regular  in  their  mode  of  occurrence,  and  they 
have  been  formed  in  quite  a  different  manner;  sometimes 
they  seem  to  have  been  forced  up  from  below  through  the 
stratified  rocks,  or  spread  out  over  their  surfaces  in  the 
manner  of  lava  currents  from  volcanoes.     Occasionally, 
igneous  rocks  occur  regularly  stratified  between  beds  of 
ordinary  stratified  rocks,  but  such  beds  are  rarely  of  very- 
great  extent. 

12.  Metamorphic  Rocks. — Besides  the  ordinary  strati- 
fied rocks,  and  those  which  are  clearly  unstratified,  are 
others  which  occur,   indeed,  in  regular  order  like  the 
former,  but  which  appear  to  have  been  much  altered  by 
heat,  pressure,  electricity,  or  other  agencies.     They  are 
generally  harder,  much  more  crystalline,  and  frequently 
contain  rich  stores  of  valuable  materials.     These  are  the 
so-called  metamorphic  rocks.    Among  the  more  important 
of  the  regular  stratified  rocks  may  be  mentioned  lime- 
stone and  sandstone;  granite,  greenstone,  and  el  van  por- 
phyry, are  common  unstratified  rocks;    while    roofing- 
slate,  mica-schist,  and  gneiss  are  metamorphic.     These 
will  be  more  minutely  described  in  the  next  chapter. 

The  stratified  rocks,  as  already  said,  are  found  to 
succeed  each  other  in  a  regular  series;  having,  however, 
frequently  some  of  its  members  missing,  but  not  occurring 
in  a  reversed  order.  Of  this  series,  those  which  appear 
at  the  top,  or  nearest  the  surface,  are  necessarily  the  most 
recent.  :' 

13.  Igneous  Rocks. — The  igneous  rocks  are  of  various 
ages,  some  masses  of  granite,  for  example,  being  much 
more  recent  than  others.     The  stratified  and  metamorphic 


GEOLOGY   OP   MINING   DISTRICTS. 


17 


rocks  were  originally  deposited  horizontally,  or  nearly  so, 
although  now  frequently  found  much  disturbed,  or  rest- 
ing upon  the  irregular  surfaces,  or  edges  of  older  rocks; 
unstratified  rocks  occur  under  almost  every  possible 
condition.  Fig.  1  shows  the  stratified  metamorphic 
"devonian"  shales  or  "  killas,"  a,  resting  upon  the 
irregular  surface  of  granite;  b,  at  the  mines  north  and 
south  of  Carn  Brea  Hill  in  Cornwall. 


m 


25 


Av 


Fig.  1. — a,  Killas;  b,  granite;  c,  elvan. 
The  following  table  gives  the  names  of  the  leading 
groups  or  divisions  of  stratified  rocks,  including  references 
to  some  of  the  chief  mineral  deposits  occurring  in  them 
which  are  of  interest  to  miners. 

No.        Formation.  Chief  Mineral  Contents. 

1.  Post  Tertiary. —Stream  tin  of  Cornwall  in  river  gravels. 

Copper  deposits  of  Lake  Superior.  Allu- 
vial gold  of  Australia  and  California. 

2.  Pliocene Large  deposits  of  bones  and  excrement  of 

fishes  (known  as  coprolites),  obtained  by 
a  rude  species  of  mining  from  Suffolk 
and  Essex,  and  used  for  making  artificial 
manures. 

3.  Miocene Some  of  the  lignites  or  brown  coals  of  Ire- 

land are  of  this  age.  Lignite  beds  of 
Bovey  Tracey  in  Devon,  Antrim,  Mull, 
Austrian  Alps,  Germany,  and  Van- 
couver's Island. 

4.  Eocene Lignites    of    Tyrol,   Venetian    Alps,    and 

Southern  Styria.  Gypsum  of  Montmartre. 

5.  Cretaceous Iron  ore  beds  of  Sussex.     Copper  ores  of 

Algiers  and  Chili.  Lignite  of  Gosau,  in 
the  Austrian  Alps,  and  of  Santa  Fe  de 
Bogota,  in  S.  America,  Coal  of  Moravia. 

ISu  B 


18  PRINCIPLES   OP   METAL   MINING. 

No.        Formation.  Chief  Mineral  Contents. 

G.  Oolitic  &  Liassic.— Coal  of  Kimmeridge,  Brora,  Funfker- 
chen,  and  Steierdorf,  in  S.  Hungary; 
Pennsylvania.  Brown  coal  of  N.  Ger- 
many. Copper  deposits  of  the  Bannat, 
in  Austria,  and  of  Department  1'  Avey- 
ron,  in  France.  Iron  ores  of  Cleveland 
and  Rosedale,  in  Yorkshire. 

7.  Trias "Letterkohle"  of  South  Germany.     Coal 

of  Virginia,  U.S.,  and  of  New  South 
Wales  (part).  Copper  of  Chessy,  in 
France.  Lake  Superior,  Connecticut, 
New  Jersey,  and  Pennsylvania  (accord- 
ing to  some  authors). 

8.  Permian.- "Branschiefer"  of  Germany  and  Bohemia. 

Coal  of  India  and  of  New  South  Wales 
(part).  Copper  deposits  of  the  west  side 
of  the  Ural  Mountains.  Mansfeld,  in 
Prussia;  Hesse,  Thuringia.  Rock  salt 
of  Worcestershire  and  Cheshire.  Clay 
ironstone  of  the  coal  measures. 

9.  Carboniferous.  ..Coal  measures  of  Gt.  Britain  and  Ireland, 

France,  Belgium,  Prussia,  Bohemia,  Mor- 
avia, Spain,  United  States,  and  Nova 
Scotia.  Anthracite  of  South  Wales, 
Ireland,  and  Pennsylvania.  Coal  of 
New  South  Wales  (part).  Lead  mines 
of  Derbyshire  and  Cumberland. 

10.  Devonian Coal  of   New  South  Wales   (part).     Tin, 

copper,  iron,  and  lead  lodes  of  Cornwall 
and  Devon.  Copper  lodes  of  Wexford. 

11.  Silurian Anthracite  of  County  Cavan,   Ireland;  of 

Isle  of  Man  and  Norway.  Graphite  of 
Cumberland.  Copper  of  the  east  flank 
of  the  Urals. 

12.  Cambrian 

13.  Laurentian Graphite  beds  of  North  America.     Copper 

of  Norway  and  Sweden. 

Some  of  these  mineral  deposits  occur  as  if  filling  up 
the  irregular  fissures  known  as  veins  or  lodes;  others 
occur  as  regular  seams  or  beds.* 

14.  Tin,  copper,  iron,  and  other  minerals,  also  occur  in 

*  It  should  be  mentioned  that  the  veins  are  frequently  much 
newer  in  their  formation  than  the  rocks  in  which  they  occur,  but 
jt  cannot  always  be  said  how  much  newer, 


GEOLOGY  OP  MINING  DISTRICTS.  19 

granite,  greenstone,  and  other  rocks  of  various  ages,  near 
their  junctions  with  the  aqueous  or  metamorphic  rocks. 
China  clay  is  very  seldom  obtained  by  mining,  and  will 
not  therefore  be  here  further  alluded  to.  It  occurs  in 
connection  with  most  of  the  granite  masses  of  the  west 
of  England. 

15.  Coal  or  Lignite  occurs  also  in  China,  Japan,  New 
Zealand,    the   Falkland   Islands,    and   in    South-eastern 
Africa,  but  the  geological  age  of  the  containing  rocks  is 
somewhat  uncertain.    Igneous  rocks  occur  in  every  one  of 
the  foregoing  series  of  rocks,  and  are  often  sought  for  as 
building  or  ornamental  stones,  or  for  road  metal.     They 
are   of  two   kinds,    called  "volcanic"   and  "plutonic." 
Volcanic  rocks,  such  as  lava,  pumice,  basalt,  etc.,  have 
been  thrown  out  from  volcanoes  in  a  melted  or  half  melted 
state,  and  have  afterwards  cooled  down  into  solid  masses. 
Plutonic  rocks,  such  as  granite  and  porphyry  (elvan),  seem 
to  have  been  formed  at  greater  depths,  and  under  a  pres- 
sure  of  many  thousand  feet  of  rock.     They  are  now 
visible  through  the  removal  by  denudation  of  their  cover- 
ing rocks.     "Elvans"  are  shown  at  cc  in  fig.  1. 

To  the  metal  miner  these  igneous  rocks  are  of  especial 
interest,  as  it  is  but  seldom  that  very  rich  deposits  of  ore 
are  found  at  any  great  distance  from  them.  Their  dis- 
turbing influence  of  the  surrounding  stratified  rocks  seems 
often  to  be  the  cause  of  such  deposits;  but  although  this 
is  so  on  the  large  scale,  it  is  not  always  so  in  detail. 
Sometimes  in  Cornwall,  for  instance,  elvan  courses 
"make"  very  rich  deposits;  at  other  times,  but  not  so 
commonly,  their  immediate  influence  seems  to  be  un- 
favourable. 

16.  The  different  substances  sought  for  by  the  miner 
occur  usually  either  in  "veins"  or  in  "beds,"  but  some- 
times in  "irregular"  deposits  known  as  "pockets,"  "car- 
bonas,"  etc.     The  ores  of  tin,  copper,  lead,  zinc,  and  many 
other  metals  occur  mostly  in  "  rake"  veins  or  "  lodes,"  or 
in  "pipe"  veins  or  "shoots,"  but  occasionally  in  pockets 
or  alluvial  beds,    Coal  occurs  always  in  beds,    Iron,  very 


20  PRINCIPLES   OF   METAL  MINING* 

frequently,  in  all  the  different  forms  of  deposit.  The  tools 
and  appliances  for  these  different  kinds  of  mining  are  on 
the  whole  a  good  deal  alike,  but  lodes  and  beds  are  so 
essentially  different  in  their  conditions  that  very  different 
modes  of  working  are  found  necessary,  and  it  will  be  well 
to  distinguish  them  from  the  outset.  Irregular  deposits 
or  pockets  are  worked  by  one  or  the  other  method,  or  by 
modifications,  including  some  of  the  peculiarities  of  each, 
as  may  be  found  necessary  in  each  peculiar  case.  The 
chief  peculiarities  of  vein  mining  and  bed  mining  are 
detailed  in  the  Sixth  and  following  chapters. 


CHAPTER  III. 

MINERALS   AND   ROCKS. 

17.  ANY  natural  substance  which  is  not  of  animal  or 
vegetable  origin,  and  which  is  in  all  parts  of  the  same  com- 
position, is  called  a  mineral.     Among  miners,  however, 
the  term  is  only  applied  to  such  substances  as  are  usually 
obtained  from  mines.      These  are  more  properly  called 
ores.     Coal,  also,  although  of  vegetable  origin,  and  there- 
fore excluded  by  the  strict  application  of  the  above  defini- 
tion, must  be  here  included  with  them. 

18.  Composition  of  Rocks. — Many  rocks  are  made  up 
of  two,  three,  or  more  distinct  minerals;  others  consist  of 
impure  masses  of  some  one  mineral.     Thus,  the  well- 
known  rock  called  granite  is  a  mixture  of  the  three 
minerals,  quartz,  felspar,  and  mica;  while  ordinary  lime- 
stone is  a  mass  of  more  or  less  impure  carbonate  of  lime, 
or  calcite.     Hematite,  limonite,  rock  salt,  coal,  and  many 
others  of  the  substances  mentioned  below  occasionally 
thus  ocour  as  rock  masses. 

19.  Every  miner  should  be  well  acquainted  with  the  more 
commonly  occurring  minerals,  and  the  rocks  formed  from 
them,  and  especially  witli  those  mentioned  in  the  follow- 


MINERALS  AND  ROCKS.  21 

ing  lists.    Pure  specimens  of  these  contain  the  percentages 
of  the  metal  sought  as  shown  in  the  second  column. 

L— METALLIC  MINERALS  OP,  ORES. 

Name.  Native  Metals.  per  cent,  of  MetaLs. 

Gold,  .  100 


Silver, 

Platinum, 

Mercury, 

Copper, 

Bismuth, 


100 
100 
100 
100 
100 


SILVER  ORES. 

Argentite,  or  grey  silver  ore,         .  .  87 

Stephanite,  or  brittle  silver  ore,    .  ;•  70 

Pyrargyrite,  or  dark  red  silver,     .  .  59 

Proustite,  or  light  red  silver,         .  .  65 

Kerargyrite,  or  horn  silver,            .  .  75 

MERCURY  ORE. 

Cinnabar,    .           .           .  .  86 
COPPER  ORES. 

Cuprite,  or  red  oxide  of  copper,     .  .  89 

Melaconite,  or  black  oxide,            .  .  79 

Chalcocite,  or  grey  copper  ore,      .  .  80 

Chalcopyrite,  or  yellow  copper  ore,  .  34 

Erubescite,  or  purple  copper  ore,  .  55 

Malachite,  or  green  copper  ore,     .  .  57 

Chessylite,  or  blue  copper  ore,       .  .  55 

TIN  ORE. 

Cassiterite,  or  tin  ore,        ...  79 

LEAD  ORES. 

Galena,  or  lead  glance, 

Cerussite,  or  carbonate  of  lead,     .  .  71 

Anglesite,  or  sulphate  of  lead,        .  .  70 

Pyromorphite  or  phosphate  of  lead,  .  76 

IRON  ORES. 

Magnetite,  or  black  oxide  of  iron, 

Hematite,  or  red  oxide  of  iron,      .  . 

Limonite,  or  brown  oxide  of  iron,  .  59 

Chalybite,  or  carbonate  of  iron,     .  .  42 


22  PRINCIPLES   OF  METAL  MINING. 

ZINC  ORES. 

Name.  per  cent,  of  Metals. 

Blende,  or  "  Black  Jack,"  .  .  67 

Calamine,  or  carbonate  of  zinc,     .  .  52 

MANGANESE  ORE. 
Pyrolusite,  or  oxide  of  manganese,  .  63 

TUNGSTEN  ORE. 
Wolfram,  or  tungstate  of  iron,       ...  CO 

ANTIMONY  ORE. 
Antimonite,  or  grey  antimony  ore,  .  71 

20.  Besides  these,  iron  pyrites,  or  "  mundic,"  is  often 
wrought  as  an  ore  of  sulphur,  of  which  it  contains  54 
per  cent.  It  also  frequently  contains  small  quantities  of 
copper,  silver,  and  gold. 

2.— NON-METALLIC  MINERALS  OR  SPARS. 

Quartz,  or  "spar." 

Fluor  spar,  blue  John  or  cann. 

Calcite,  or  carbonate  of  lime. 

Mica,  or  "shell." 

Gypsum,  or  sulphate  of  lime. 

Hornblende. 

Serpentine. 

Dolomite. 

Chlorite,  or  peach. 

Schorl,  or  cockle. 

Barytes,  or  heavy  spar. 

Bock  salt, 

Coal. 

These  are  the  most  important  of  the  minerals  which 
will  come  under  the  notice  of  the  young  miner,  who  would 
do  Well  to  make  himself  acquainted  very  minutely  with 
their  peculiarities  and  properties,  by  the  examination  and 
comparison  of  actual  specimens  if  possible.* 

*  Complete  descriptions  of  these  and  many  other's,  with  Which 
he  may  meet  from  time  to  time,  will  be  found  in  the  author's 
First  Book  of  Mineralogy,  published  in  the  present  series  of  text- 
books. 


MINERALS  AND  ROCKS.  23 

21.  The  student  should  also  make  himself  acquainted 
with  the  rocks  mentioned  below.  This  will  be  easy  after 
he  knows  well  the  minerals  already  mentioned. 

Granite. — A  granular  compound  of  quartz,  felspar,  and  mica. 

Gneiss. — A  foliated  compound  of  the  same  minerals  arranged 
in  irregular  layers. 

El  van. — Nearly  the  same  ingredients,  but  differently  arranged. 
The  mass  of  the  rock  is  frequently  an  uncrystallised  felspathic 
substance,  through  which  crystals,  or  rounded  grains  of  quartz, 
and  crystals  of  felspar,  or  flakes  of  mica  are  interspersed. 

Syenite. — A  granular  compound  of  quartz,  felspar,  and  horn- 
blende, often  much  like  granite  in  appearance. 

Schorlyte,  or  Schorl  Rock. — A'granular  compound  of  quartz  and 
schorl.  Occasionally  the  quartz  disappears,  and  the  schorl  forms 
a  very  compact  mass  of  somewhat  dull  and  earthy  appearance, 
very  hard  and  tough. 

Felsyte. — A  granular  compound  of  quartz  and  felspar. 

Mica' Schist. — A  foliated  compound  of  quartz  and  mica. 

Quartzyte. — A  granular  rock  composed  of  quartz  only. 

Serpentine. — The  massive  impure  form  of  the  mineral  of  the 
same  name;  feels  smooth  and  somewhat  greasy,  and  is  easily 
scratched  with  a  knife. 

Greenstone,  Whinstone,  or  Trap. — A  compound  of  some  kind 
of  felspar  with  hornblende;  sometimes  granular,  but  more  fre- 
quently compact.  It  frequently  contains  much  magnetic  iron 
diffused  through  it  in  grains.  It  is  sometimes  called  diorite. 
Miners  often  call  it  ironstone. 

Basalt  is  much  like  Greenstone  in  appearance,  but  is  much  less 
tough  and  hard,  and  usually  somewhat  heavier.  The  so-called 
toadstone  of  the  coal  and  iron  districts  of  the  centre  of  England 
is  a  kind  of  basalt. 

Clay  Slate  differs  much  in  different  districts.  One  form  is  very 
hard,  and  splits  up  readily  into  large  strong  plates,  much  used 
for  roofing.  In  another  kind,  the  "  killas  "  of  the  Cornish  miner, 
the  cleavage  is  less  perfect,  and  the  rock  is  more  brittle. 

Limestone  is  the  massive  form  of  the  mineral  calcite. 

Dolomite  is  the  massive  form  of  the  mineral  of  the  same  name. 

Gypsum  is  the  massive  form  of  the  mineral  of  the  same  name. 

Many  other  rocks  will  come  under  the  notice  of  the 
miner;  but  a  correct  appreciation  and  recognition  of  these 
will  be  of  great  assistance  to  him  in  his  explorations. 


24  PRINCIPLES  OP  METAL 

CHAPTER  IV. 

THE  NATURE  OF   MINERAL   VEINS. 

MINERAL  veins  occur  mostly  in  three  different  forms, 
known  as  Rake-veins,  Pipe-veins,  and  Flats. 

22.  Eake-veins  or  Lades  appear  to  occupy  fissures  in 
the  earth,  sometimes  parallel  to,  sometimes  cutting  across, 
the  general  bedding,  and  even  the  cleavage  of  the  rocks. 
They  are  generally  very  irregular,  often  several  miles  in 
length,  of  a  width  varying  from  less  than  one  inch  to 
many  feet,  and  they  extend  downwards  to  an  unknown 
depth.     Their  contents  vary  extremely,  some  parts  con- 
taining ores,  others  being  filled  with  matter  of  no  com- 
mercial value.     The  orey  parts  are  often  spoken  of  as 
"  shoots  of  ore."    When  the  orey  parts  are  wide  and  rich, 
and  separated  from  similar  riches  by  thin  and  unproduc- 
tive parts,  they  are  in  some  districts  called  "gash- veins." 
A  cross  section  of  a  remarkable  group  of  lodes  at  Wheal 
Basset  Copper  and  Tin  Mine,  in  Cornwall,  is  given  on 
fig.  2,  on  a  scale  of  seventy  fathoms  to  one  inch. 

23.  Pipe-veins  are  masses  of  ore,  generally  parallel  to 
the   stratification  of   a   country,  very  regular  in  their 
dimensions,  but  often  greatly  extended  in  the  direction 
of  the  dip  of  the  rocks.     They  are  more  numerous  in 
limestone  than  in  slaty  rocks. 

24.  Flats  or  Floors  consist  of  layers  of  mineral  matter 
lying  more  or  less  horizontally  between  the  beds  of  their 
containing  rocks,  and  sometimes  forming  a  connection 
between  two  parallel  lodes. 

25.  In  connection  with  some  lodes,  irregular  masses  of 
mineral  matter,  called  carbonas,  are  found.      There  are 
irregular  bunches,  of  sometimes  very  many  fathoms  in  each 
direction,  and  often  attached  to  the  lode  by  very  small 
portions  or  "  pipes  "  of  ore.     In  some  places,  where  the 
lodes  are  very  narrow  and  numerous,  the  whole  rock  seems 
to  be  permeated  with  mineral  matter,  which  is,  never- 


THE  NATURE   OP  MINERAL  VEINS. 


25 


theless.  accumulated  in  the  thin  veins  referred  to,  and  in 
the  joints.  These  are  in  Germany  called  stockwerke.  No 
English  name  has  come  into  common  use,  but  they  are 
occasionally  spoken  of  as  "stockworks." 


Fig.  2.* — a,  a,  Killas;  &,  b,  granite;  c,  c,  elvan. 

26.  Of  these  different  kinds  of  mineral  deposits,  the  lodes 
are  certainly  the  most  important;  and  as  they  are  very 
numerous,  and  have  been  largely  worked  in  the  west  of 
England,  our  description  will  apply  chiefly  to  that  dis- 
trict. 

Many  of  these  have  evidently  been  opened  several 
times  successively,  and  filled  in  more  or  less  completely 
with  matter  of  different  kinds.  Evidence  of  this  is 
afforded  by  the  "  combed,"  "  brecciated,"  and  "  conglome- 
rate "  structure  frequently  met  with  in  lodes.  Besides 
the  actual  filling  in  of  the  fissure,  the  country  on  each 

*  This  figure  is  from  a  survey  by  Capt.  Maynard  of  East  Pool 
Mine. 


6  PRINCIPLES   OP   METAL   MIKING. 

side  is  frequently  much  altered,  "  mineralised  "  as  miners 
say.  This  altered  band,  which  in  tin  mines  is  often  suf- 
ficiently rich  to  pay  for  removal,  is  variously  known  as 
capel,  stickings,  selvage,  and  by  several  other  names.  In 
some  parts  of  Cornwall,  especially  in  the  china  clay  dis- 
tricts, the  tin  lodes  are  little  more  than  highly  mineral- 
ised "joints,"  only  rich  at  intervals,  but  sometimes  the 
clay  appears  to  have  been  indurated  and  impregnated 
with  quartz,  schorl,  and  tin  ore  for  many  feet  on  each 
side  of  the  actual  fissure,  especially  in  the  neighbourhood 
of  certain  cross-veins. 

Sometimes  these  mineralised  joints  are  so  numerous 
that  the  whole  mass  of  rock  has  to  be  removed,  and  after- 
wards picked  over,  or  dressed  entire.  This  is  the  case  in 
many  places  about  the  centre  of  Cornwall,  the  works  re- 
sembling the  so-called  "stockwerke"  of  Germany.  Such 
works  are  usually  rather  quarries  than  mines,  and  the 
author  has  known  a  produce  of  only  3J  Ibs.  of  saleable 
tin  ore  in  the  ton  of  stuff,  to  yield  a  profit  for  years 
together. 

27.  The  principal  tin  and  copper  lodes  of  each  mining 
district  in  Cornwall  and  Devon  occur  in  parallel  groups, 
and,  on  the  whole,  have  a  bearing  differing  but  little 
from  that  of  the  granite  axis  of  the  two  counties.  From 
Tavistock  to  Hayle  this  axis  bears  about  E.N.E.,  but 
from  Hayle  to  the  Land's  End,  a  marked  change  of  direc- 
tion occurs,  and  this  is  accompanied  by  a  similar  change 
in  the  direction  of  the  lodes.  Very  similar  facts  may  be 
observed  in  other  mining  districts  all  over  the  world. 

Lodes  very  seldom  pass  perpendicularly  into  the  earth, 
for  more  frequently  they  have  an  inclination,  dip,  or  under- 
lie one  way  or  the  other,  as  shown  in  fig.  3,  which  repre- 
sents a  lode  in  granite  underlying  south.  This  underlie 
is  in  Cornwall  'always  reckoned  at  so  many  feet  in  a 
fathom  from  the  perpendicular.  In  any  group  of  lodes, 
some  may  underlie  one  way,  some  the  other,  as  in  fig  2, 
p.  25. 

The  average  width  of  the  tin  and  copper  lodes  of  Com- 


NATURE   OF   MINERAL   VEINS. 


wall  and  Devon  is  about  3  feet  6  inches;  the  average 
underlie  is  20°  from  the  perpendicular,  or  14  inches  in  a 
fathom.  The  lodes  frequently  split  up  into  branches,  and 
sometimes  these  branches  re-unite,  when  the  included 
portion  of  country  is  called  a  "horse."  A  "horse"  is 
shown  at  g,  in  fig.  3. 

Besides  the  so-called  right 
running  or  champion  lodes, 
there  are  other  veins  known  as 
caunter  lodes,  cross  courses, 
trawns,  guides,  flucans,  or  gos- 
sans. Caunter  lodes  are  those 
which  contain  tin  or  copper,  or 
other  ores,  but  have  a  direction 
different  from  the  champion  lodes. 
They  occur  especially  in  the  cen- 
tral parts  of  Cornwall. 

28.  Cross  Courses  are  veins 
whose  direction  is  nearly  at 
right  angles  to  the  chief  lodes  of 
any  particular  mining  district. 
When  they  contain  clay  they 
are  known  as  flucans,  and  this 
clay  is  sometimes  so  very  imper- 
vious to  water,  that  they  form 
the  best  of  all  possible  boundaries 
between  neighbouring  mines. 
Sometimes  the  cross-veins  yield 
iron  ore  or  lead  ore  in  large 
quantities;  this  is  particularly  the 
case  about  the  centre  and  east  Fig.  3.—  a, a,  "Hanging 
of  Cornwall.  Near  their  points  ^  ft  ^^ 
of  intersection  with  the  lodes,  and  "capel;"e,e,  "back" 
they  frequently  contain  portions  of  lode;  f,  granite j  g, 
of  ore  similar  to  that  in  the  a  "horse." 
lode,  and  also  small  quantities  of  more  unusual  ores, 
as  those  of  cobalt,  nickel,  antimony,  and  silver.  In 
St.  Just,  the  cross  veins  are  known  as  trawns,  or  guides; 


28  PRINCIPLES  OF  METAL  MINING}. 

in  St.  Agnes,  as  gossans.  The  average  width  of  cross  veins 
is  a  little  more  than  that  of  the  lodes,  their  underlie  is 
somewhat  less,  but,  like  them,  they  dip  more  frequently 
towards  than  from  the  nearest  mass  of  granite.  In 
other  respects  they  closely  resemble  the  lodes,  having 
similar,  although  somewhat  less,  variations  in  width, 
underlie,  contents,  etc.  They  also  split  and  re -unite  like 
the  lodes,  but  perhaps  not  so  frequently. 

Fig.  4  shows  the  mean  bearing  of  the  tin  and  copper 

lodes,  caunters,  and 
cross  courses  in  Corn- 
wall. The  experience 
gained  in  Cornwall 
and  West  Devon  has 
made  the  miners  of 
this  district  famous 
in  all  parts  of  the 
world,  and  their 

Fig.  4. — MEAN  DIRECTION  or  TIN  AND  services  are  in  con- 
COPPER  LODES,  CROSS  VEINS,  AND  tinuai  requisition  for 
CAUNTERS  IN  CORNWALL.  ^  di^)very  and 

working  or  "  exploitation"  of  mineral  veins.  In  search- 
ing for  minerals  in  untried  countries,  they  are,  in  the 
first  instance,  guided  by  the  general  conformation  of 
the  country.  Practically,  the  unlearned  Cornishman  has 
looked  for  a  surface  contour  more  or  less  resembling  that 
of  Cornwall  in  its  undulating  character,  and  has  especially 
searched  the  flanks  and  bases  of  hills  of  moderate  eleva- 
tion for  the  outward  signs  of  mineral  wealth.  Among 
these  outwards  signs  may  be  mentioned,  "  shodes,"  "  gos- 
sans," "springs,"  and  "stains,"  visible  either  in  such 
situations,  in  mole-hills,  the  ejecta  of  burrowing  animals, 
the  sides  of  ravines  and  water-courses,  etc.  He  also  closely 
examines,  all  such  river  sands  as  may  come  in  his  way  by 
vanning. 

29.  Shodes  are  stones  of  ore,  often  more  or  less  water- 
worn,  which  are  recognised  by  the  miner  as  similar  to 
those  he  has  seen  near  the  backs  of  lodes.  He  argues 


THE    NATURE   OF   MINERAL   VEINS.  29 

that  such  stones  can  only  be  brought  by  natural  agencies 
down  hill,  and,  therefore,  goes  upwards,  searching  as  he 
goes,  until  such  shodes  no  longer  appear.  At  or  near  the 
point  of  disappearance,  he  searches  for  the  lode  by  the 
method  of  "  costeaning,"  presently  to  be  described. 

30.  Gossan  (pronounced  gozzan)  is  the  name  given  to  the 
cellular  quartz  and  ferruginous  matter,  frequently  found 
in  large  quantity  at  the  outcrop  or  back  of  a  lode.     The 
existence  of  much  gossan  indicates  more  especially  lodes 
of  copper,  lead,  iron,  sometimes  of  gold  or  silver  j  but  tin 
lodes  have  frequently  no  gossan. 

31.  Springs  of  water  frequently  indicate  the  outcrop 
of  a  lode,  and  even  in  seasons  where  no  water  is  visible, 
a  slight  depression  or  a  superior  greenness  of  the  herbage 
often  indicates  their  position  with  accuracy. 

32.  Stains  of  various  kinds  often  occur  in  connection 
with  these  springs.     Thus,  stains  of  red,  yellow,  or  brown, 
very  frequently  indicate  the  existence  either  of  iron  lodes, 
or  of  the  iron  gossans  of  other  lodes.     Green  and  blue 
stains   frequently  indicate   deposits   of  copper;  greyish, 
bluish,  or  slaty  tints,  often   indicate  lead.     Some  lodes 
have  been  discovered  by  the  exposure  of  the  sides  of 
ravines,    produced    by   running   water;    others,   by   the 
character  of  the  material  thrown  out  by  moles  or  other 
burrowing  animals  from  their  galleries.     Some  have  been 
discovered  by  farmers  in  the  material  thrown  out  by  the 
plough,  by  miners  working  alluvial  deposits,  or  by  men 
engaged  in  making  railway  cuttings,  or  opening  quarries. 

33.  A  very  perfect  cleavage  in  the  rocks,  or  a  very  dis- 
tinct porphyritic  structure  in  the  granite  rocks  of  any 
neighbourhood  are  not  looked  upon  as  favourable  indica- 
tions.   On  the  other  hand,  if  the  component  minerals  of  the 
igneous  rocks  appear  indistinctly  blended  into  each  other, 
the  cleavage  of  the  slaty  rocks  indistinct,  and  the  separate 
plates   not   too  glossy,  the  indications  are  regarded  as 
favourable,  if  they  occur  in  a  suitable  situation. 

34.  The  process  of  costeaning  has  been  already  referred 
to.    It  is  as  follows :  The  general  bearing  of  the  lodes  of  any 


30  PRINCIPLES   OE   METAL   MINING. 

district  is  first  ascertained  by  the  discovery  of  some  one 
champion  lode,  or  by  the  general  indications  of  the  country. 
Let  us  suppose  this  general  bearing  to  be,  as  in  Cornwall, 
nearly  east  and  west.  Pits  are  then  sunk  in  likely  situa- 
tions, say  from  5  to  20  or  30  fathoms  apart,  and  deep 
enough  to  be  below  the  disturbed  subsoil  or  alluvial 
deposit  of  the  place.  These  pits,  in  the  case  indicated, 
will  be  in  a  line  nearly  north  and  south.  A  gallery  or 
level  is  then  drawn,  so  as  to  make  a  communication  be- 
tween these  pits,  and  in  doing  so  the  lode,  if  situated 
between  any  two  pits,  cannot  fail  to  be  discovered.  This 
process  is  called  costeaning,  and  it  is  on  the  whole  the 
very  best  which  can  be  adopted  in  ordinary  cases,  and 
much  preferable  for  the  purpose  to  the  boring  which  is 
so  commonly  and  properly  resorted  to  in  bed  mining. 


CHAPTER    V. 

"  HEAVES,"   ETC. 

35.  IN  following  a  lode  it  frequently  happens  that  a 
cross- vein  is  reached,  after  cutting  through  which  the  lode 
is  not  to  be  found  on  the  other  side.     In  such  cases  it  is 
said  to  be  "  heaved,"  and  it  becomes  necessary  to  drive  on 
the  cross-vein  in  order  to  discover  it  again.     These  heaves 
are  a  source  of  much  loss  to  the  miner  and  his  employers, 
as  they  are  sometimes  of  great  extent,  occasionally  as  much 
as  70  fathoms;  so  that  it  is  a  matter  of  great  importance 
to  the  miner  to  be  able  to  say  in  which  direction  he  is 
most  likely  to  find  it  by  driving.     No  rule  can  be  given 
which  has  absolutely  no  exceptions,  but  a  very  high 
degree  of  probability  is  attainable. 

36.  Direction  of  Heaves. — If  the  lode  is  found  by 
driving  to  the  right  on  the  cross-vein,  it  is  said  to  be  a 
right  hand  heave;  if  to  the  left,  a  left  hancl  heave.     In, 


HEAVES. 


31 


Kg.  5. 


In  Corn- 


figs.  5  and  6  the  lodes  are  heaved  to  the  left,  whether  the 
miner  is  approaching  the  cross-vein  from  the  east  or  the 
west.  In  Cornwall, 
many  more  right 
hand  than  left  hand 
heaves  are  known. 

It  is  but  seldom 
that  the  lode  and 
cross-course  form  an 
intersection  at  right 
angles  as  in  fig.  5; 
far  more  frequently 
a  greater  angle  and 

a  smaller  angle  are  observable  as  in  fig.  6. 
wall,  of  272  cases  of 
intersection  record- 
ed by  Mr.  Henwood, 
57  were  unaccom- 
panied by  heaves; 
and  of  the  215  re- 
maining, 1 8 1 ,  or  more 
than  84  per  cent., 
were  found  by  driv- 
ing on  the  side  of  the 
greater  angle;  and  Fig- 

34,  or  less  than  16  per  cent.,  on  the  side  of  the  smaller 
angle.  In  other  words,  by  driving  on  the  side  of  the 
greater  angle,  there  are  five  chances  to  one  that  the  lode 
will  be  met  with. 

Even  this  is  not  all  that  the  study  of  known  intersec- 
tion teaches.  Several  other  rules  will  add  largely  to  the 
chances  of  success.  Thus  parallel  lodes  of  similar  un- 
derlie will  be  heaved  in  the  same  direction  in  the  great 
majority  of  cases.  Those  with  the  greatest  underlie  will 
mostly  be  heaves  to  the  greatest  extent.  Lodes  of  similar 
bearings  having  opposite  underlie,  will  not  unfrequently 
be  heaved  in  opposite  directions.  By  studying  the  bearing 
and  underlie,  therefore,  of  other  lodes  intersected  by  the 


32 


PRINCIPLES   OP   METAL   MINING. 


cross-course  in  question,  much  additional  information  will 
be  gained. 

37.  Extent  of  Heaves.— Some  idea  of  the  extent  of 
the  heave  may  also  be  obtained  in  many  instances,  as  it 
has  been  observed  that  the  heaves  occasioned  by  large 


Fig.  7. 

cross-courses  are  mostly  greater  than  those  occasioned  by 
small  ones.  Fig.  7  shows  the  heaves  of  three  lodes  and 
two  elvans  by  a  cross-course  in  the  neighbourhood  of 


Fig.  8. 

Camborne,  in  Cornwall.      The  science  of  Geology  very 
fairly  accounts  for  these  phenomena  in  many  instances; 


HEAVES. 


33 


but  the  elementary  student  of  mining  had  better  defer 
his  study  of  such  theoretical  matters.  ..-,.,,- 

38.  Indications. — The  direction  of  the  heave  is  some- 
times  indicated  by  stains  in  the  cross- 
course,  a  change  in  its  mineral  character, 

a  stream  of  water,  or  even  by  leaders  of 
ore  which  connect  the  two  parts  of  the 
lode,  as  shown  in  fig.  8.  All  such  ap- 
pearances will  be  carefully  sought  for 
and  noted  by  the  young  miner  who 
wishes  to  succeed. 

39.  Slides  are  displacements  of  lodes 
occasioned  by  thin  veins,  often  of  clay, 
which  have   a  general   bearing  similar 
to   that  of    the    lode,    but   a   different 
underlie,  as  in  fig.  9.     Such  slides  are 
by  no  means  so  common  as  heaves. 

A  kind  of  reversed  slide,  shown  in  fig. 
10,  which  throws  up  the  lode,  is  not  uncommon  in  the 
mines  of  St.  Agnes,  Cornwall.  As  the  disturbing  vein  con- 
tains ferruginous  matter, 
much  like  the  gossan 
found  on  the  outcrop  of 
many  lodes,  the  slide  itself 
is  here  frequently  called 
a  gossan.  As  a  rule,  slides 
are  by  no  means  so  com- 
mon as  heaves — and  they 
are  often  still  less  liked  by  Fig.  10. 

the  miner  than  heaves.  The  gossans  of  St.  Agnes,  how- 
ever, are  in  some  respects  a  positive  advantage,  as  they 
bring  up  the  lode  nearer  the  surface,  where  it  can  be 
more  easily  and  cheaply  worked. 


Fig.  9. 


188 


34  PRINCIPLES   OF   METAL   MINING, 

CHAPTER  VI. 

DEAD   WORK   IN   VEIN   MINING. 

40.  Dead  Work. — Tins  includes  all  such  mining  opera- 
tions as  are  carried  on  underground  for  the  purpose  of 
obtaining  the  ore,  excepting  only  the  actual  "getting." 
It  will  therefore  include  all  the  shafts  sunk  and  levels 
driven,  not  only  at  the  commencement  of  the  undertak- 
ing, but  also  such  works  as  are  or  ought  to  be  kept  in 
advance  of  the  productive  portions  of  the  mine,  so  as  to 
yield  a  continual  output.      Productive  work  is  a  term 
applied  to  the  actual  getting  of  the  ore  so  "  laid  open." 

41.  Shafts. — The  situation  and  underlie  of  the  lode 
having  been  sufficiently  ascertained  by  the  preliminary 
explorations,  one  or  more  shafts  are  now  sunk,  generally 
on  the  side  to  which  the  lode  inclines;  or  if  there  be  two 
or  more  lodes  near  to  each  other,  between  these. 

42.  Drainage. — As  this  shaft  soon  becomes  full  of 
water,  at  least  in  its  lower  part,  it  becomes  necessary  to 
devise  some  means  of  drainage.     Sometimes  this  can  be 
effected,  partly  or  entirely,  by  driving  a  level  from  the 
nearest  low  ground,  so  as  to  reach  the  shaft  in  depth. 
Such  a  level  is  called  an  "  adit."     Adits  are  frequently 
of  great  importance  to  the  mines  drained  by  them,  and 
should  always  be  kept  in  thorough  repair,  as  even  in  the 
case  where  pumping  is  necessary  for  the  workings  below 
the  adit,  the  amount  of  pumping  power  required  may  be 
much  reduced  by  only  raising  the  water  to  the  adit  level, 
instead  of  lifting  it  at  once  to  surface. 

From  the  shaft,  both  above  and  below  the  adit,  levels 
are  driven  right  and  left,  often  at  distances  of  10  fathoms, 
or  60  feet,  apart.  As  these  levels  become  extended,  it  is 
necessary  to  open  communication  between  them  by  means 
of  smaller  shafts  or  "winzes,"  which  do  not  reach  the  sur- 
face, for  purposes  of  ventilation,  and  also  as  a  means  of 
discovering  the  nature  of  the  lode  between  the  levels. 


DEAD  WORK   IN  VEIN   MINING.  35 

Fig.  11  shows  the  various  "shoots  of  ore"  in  part  of 
Snailbeach  mine,  laid  open  by  means  of  the  levels  there 
shown.  Similar  shoots  of  ore  occur  in  the  lodes  of  Corn- 
wall, but  they  are  connected  by  poorer  portions  of  the 
lode  instead  of  being  separated  by  masses  of  killas. 


Fig.  11. — SHOWING  SHOOTS  OF  ORE  AT  SNAILBEACH  MINE,  a,  a, 
Adit  level;  6,  shaft;  c,  d}  e,  levels;/,/,  shoots  of  ore  dipping 
west;  h,  h,  killas. 

43.  The  terms  "back,"  "hanging-wall,"  "foot-wall," 
and  "  end"  are  continually  used  by  miners.  In  Cornwall 
they  are  applied  as  in  fig.  3.  The  "end"  is  better  seen 
at  c  in  fig.  20,  which  is  put  a  little  in  advance  of  the 
stope  a.  The  remains  of  a  "winze,"  which  was  the 
means  of  opening  out  the  deposit  of  ore  at  a,  is  shown 
in  the  same  figure  at  d. 

>  44.  Form  and  Dimensions  of  Shaft. — The  shafts  are 
mostly  rectangular  in  section,  varying  from  5'  x  3'  up  to 
1 2'  x  9',  and  occasionally  larger.  In"  Cornwall  a  common 
size  is  10'  x  8',  and  the  shafts  are  generally  larger  in  hard 
ground  than  in  soft  ground.  This  is  for  a  double  reason 
— 1st,  that  there  is  no  difficulty  in  sinking  a  small  shaft 
in  soft  ground,  while  in  blasting  ground  a  small  shaft  is 
sunk  with  great  difficulty,  owing  to  the  want  of  room  for 
the  blasting  operations.  2nd,  the  difficulty  of  securing  the 


36  PRINCIPLES  OF   METAL 

sides  of  a  shaft  in  soft  ground  increases  rapidly  with  the 
size  of  the  shaft,  especially  when  the  section  is  rect- 
angular, while  there  is  no  such  difficulty  in  hard  ground. 
Shafts  in  vein  mining  are  almost  always  vertical  in 
their  first  portions,  say  from  30  to  70  fathoms,  after  which 
they  usually  follow  the  underlie  of  the  lode,  as  shown  in 
fig.  2.  Occasionally,  however,  shafts  are  made  to  follow 
the  underlie  of  a  lode  from  the  surface,  and  shafts  which 
are  vertical  throughout  are  of  late  years  not  uncommon, 
communication  being  effected  by  cross-cuts.  A  few  shafts 
are  inclined,  following  the  course  of  the  lode  instead  of  its 
underlie,  as  shown  in  fig.  12,  which  represents  the  work- 
ings around  the  Boscawen  shaft  at  the  famous  Botallack 
mine. 


Fig.  12.—  Scale,  160  fathoms  to  1  inch. 

45.  The  advantages  of  a  downright  shaft  are — greater 
ease  in  sinking  to  a  given  depth,  and  facility  for  haul- 
ing or  pumping.  Its  disadvantage  is  that,  with  inclined 
lodes — and  the  average  inclination  of  Cornish  lodes  is  20° 
from  the  perpendicular — a  considerable  amount  of  cross- 
cutting  is  necessary  at  the  different  levels. 

The  chief  advantage  of  an  underlie  shaft  is,  that  it 
affords  an  opportunity  of  testing  the  lode  in  its  neigh- 


DEAD   WORK   IN   VEIN   MINING.  37 

bourhood  for  the  whole  depth  of  the  shaft,  and  in  some 
instances  the  ore  got  from  the  shaft  itself  is  more  than 
sufficient  to  pay  the  expense  of  sinking  it.  Probably  the 
best  arrangement  for  an  extensive  mine  will  be  to  have  one 
principal  downright  shaft,  and  several  secondary  underlie 
shafts. 

46.  Security  of  Shaft. — The  shaft  having  been  pegged 
out  and  excavated  to  the  depth  of  a  few  feet,  ifc  is  generally 
necessary  to  raise  and  secure  its  brace  or  mouth.     The 
raising  is,  in  low  situations,  important  to  prevent  the 
entrance  of  surface  water;  and  a  neglect  of  such  a  pre- 
caution,  to   a   sufficient   extent,    has    occasionally  been 
followed  by  the  flooding  of  the  mine,  as  was  the  case  at 
East  Wheal  Rose  Lead  Mine  in  Cornwall  some  twenty 
years  ago,  when  the  bursting  of  a  waterspout  caused  a 
small  stream  in  the  neighbourhood  to  overflow  its  banks, 
and  the  water  getting  down  the  shaft  drowned  a  large 
number  of  men. 

Another  reason  for  raising  the  brace  of  the  shaft  is  in 
order  to  secure  a  "tip"  for  the  material  excavated;  and 
when  the  ground  is  level,  and  the  shaft  is  intended  to 
extend  to  a  great  depth,  a  considerable  addition  to  the 
height  of  the  "  brace  "  will  need  to  be  made  from  time  to 
time  on  this  account. 

47.  Timbering. — In  soft  ground  some  support  is  neces- 
sary in  all  cases  for  the  sides  of  the  shaft;  and  in  countries 
where  easily  wrought  freestone  or  limestone  is  readily 
obtainable,  no  better  plan  than  masonry  can  be  adopted. 
In  Cornwall  the  granites  and  elvans  of  the  county  have 
not  unfrequently  been  employed  with  good  effect  in  this 
way.     It  is  still  more  common,  however,  to  use  timber, 
either  that  grown  in  the  neighbourhood,  or  very  frequently 
the  fir  of  Norway.     The  brace  is  sometimes  formed  of  a 
framework  of  thick  balks  bolted  together.     Sometimes 
the  successive  timbers  of  the  shaft  are  hung  to  this  by 
bars  of  iron,  but  very  frequently  the  pressure  of  the 
''country"   is  sufficient   to  keep  the    timbers   in   their 
places. 


38 


PRINCIPLES   OP   METAL   MINING. 


For  small   and   unimportant  shafts  in  clay  ground, 
the   plan   known   as  "covered"    binding   is   frequently 

employed,  but  the  more  com« 
mon  and  approved  mode 
is  to  timber  by  "sets  and 
laths." 

In   the   covered   binding 
the  different  sets  are  made 
to  rest  upon  each  other  as 
shown  in  figs.  13,14.     They 
Fig.  13.— SETS  orCovERED  BIND-  are  sometimes  kept  in  place 
ING.   Scale,  about  4  ft.  to  1  in.  by  corner  timbers  nailed  in 
as  shown  at  at  fig.  13,  sometimes  by  notching  the  sets, 

sometimes  by  the  mere  pres- 
sure of  the  ground. 

The  method  by  sets  and 
laths  differs  from  this  in  the 
sets  being  much  thicker  and 
notched  deeply  together,  and 
in  their  being  placed  at  some 
distance,  generally  about  4 
feet,  apart.  Sometimes  short 
corner  pieces  called  "stud- 
dies"  are  placed  upright  to 
keep  the  sets  their  proper 
distance  apart,  but  this  pre- 
caution is  frequently  omit- 
ted. The  space  between  is 
Fig.  14. -SHAFT  TIMBERING,  strengthened  by  laths  which 
COVERED  BINDING.  Scale,  6  may  vary  from  1"  to  3"  in 
ft.  to  1  in.  thickness.  This  mode  is 

shown  in  figs.  15, 16,  where  a  a  are  the  sets,  b  b  the  laths. 
The  timbers  which  form  the  longer  sides  of  the  sets  are 
called  the  wall  plates,  the  shorter  pieces  are  "  end  pieces." 
Winzes  are  usually  much  smaller  than  shafts,  and  rarely 
require  timbering  except  in  clay  "  country,"  when  a  kind 
of  covered  binding  is  sometimes  put  in. 

48.  Levels, — Levels  are  now  rarely  driven  less  than  6  ft. 


fcEAD   WORK  IN  VEIN  MINING.  3d 

high  or  4  feet  wide,  often  8  feet  high  and  6  or  7  feet 
wide,  especially  in  hard  ground. 
The  increased  size  is  not  only 
better  for  ventilation,  but  is 
rendered  necessary  by  the 
almost  universal  use  of  tram- 
roads  instead  of  wheel-barrows  Fig.  15.— SHAFT  TIMBERING. 
in  modern  mines.  Levels  Timber  "set."  Scale,  about 
should  be  driven  as  truly  level  4  **• to  1  in- 
as  possible,  especially  when  long,  as,  if  the  rise  be  great, 
ventilation  is  almost  impos- 
sible. With  a  well  laid  tram- 
road,  a  fall  of  J"  to  J"  in  a 
fathom  will  be  found  sufficient. 
Levels  very  frequently  need  to 
be  timbered  more  or  less  com- 
pletely, and  although  covered 
binding  is  occasionally  used, 
the  method  of  sets  and  laths 
is  far  more  frequent.  When 
a  level  is  driven  by  the  side  of 
a  lode,  one  side  only  may  need 
timbering  in  many  instances. 

In  fig.  17  the  complete  mode 
of  timbering  levels  is  shown; 
a  a  are  the  legs,  b  the  cap,  c  the 
stretcher,  a,  6,  and  c  together 
forming  a  "  set."      The  laths  Fig.  16.— SHAFT  TIMBERING. 
are  shown  at  d,  d  d  being  the      Sets  and  Laths.    Scale,  6 
side  laths,  e  the  «  back  laths."      ft-  to  *  in- 
In  less  tender  ground  the  stretcher  at  c  is  often  omitted. 

Fig.  18  shows  the  mode  of  timbering  when  one  side 
and  the  roof  only  needs  support.  Many  other  modifica- 
tions are  used,  varying  with  the  exigencies  of  the  occasion, 
the  material  at  hand,  and  the  ingenuity  of  the  miner. 
Sometimes,  instead  of  the  timber  "legs,"  a  rough  masonry 
composed  of  the  debris  of  the  workings,  is  resorted  to,  and 
occasionally  this  material  is  built  into  a-complete  arch,  so 


40  PRINCIPLES  OF  METAL  MINING. 

dispensing  with  timber  altogether.  In  every  case  where 
timber  is  used,  the  bottom  of  the  level  should  be  made 
wider  than  the  top  or  "back,"  as  the  strength  of  the 
"cap"  rapidly  decreases  with  every  increase  of  its  length, 
and  it  is  towards  the  bottom  of  the  level  where  width  is 
most  required. 


Fig.  17.  Fig.  18. 

49.  Distance  between  Levels. — The  most  common 
distance  between  levels  is  now  10  fathoms,  measured  on 
the  underlie  of  the  lode,  but  12  fathoms  and  15  fathoms 
are  sometimes  left  between.    Formerly,  many  levels  were 
driven  only  5  fathoms  apart.     These  various  distances 
have  all  been  adopted  at  Botallack  mine,  as  shown  in 
%  12. 

Where  the  level  meets  the  shaft,  an  enlargement  is 
usually  made;  this  is  called  a  "  plat."  It  is  most  useful 
as  a  place  of  deposit  for  the  ore  previous  to  its  being  sent 
up  "  to  grass."  With  the  gradual  introduction  of  lifting 
cages,  large  plats  will  be  less  required,  and  will  no  doubt, 
in  many  cases,  be  dispensed  with. 

50.  Tutwork. — Shafts  are  sunk  and  levels  driven,  in 
Cornwall  and  elsewhere,  at  a  fixed  rate  per  lineal  fathom. 
Special  agreements  are  made  in  each  case,  subject  to  modi- 
fication at  the  end  of  the  "  take,"  which  is  mostly  for  one 


DEAD  WORK  IN  VEIN  MINING.  41 

or  two  months.      This  form  of  bargain  is  called  "tut 
work." 

The  timbering,  when  necessary,  is  sometimes  done  by 
the  miner  as  part  of  his  bargain,  and  the  excavated 
mineral  is  drawn  to  the  surface  at  his  cost.  Deductions 
are  also  made  from  the  gross  amount  of  his  earnings,  for 
powder,  candles,  tools,  etc.,  supplied  to  the  men  from  the 
stores  of  the  mine. 

Sometimes,  however,  the  timbering  is  done  by  special 
tiinbermen,  and  the  excavated  material  is  drawn  to  the 
surface  at  the  cost  of  the  employers.  The  prices  of  sink- 
ing and  driving  vary  much  according  to  the  nature  of  the 
ground,  depth  from  surface,  size  of  shaft  or  level,  and 
many  other  particulars;  but  some  idea  of  the  labour  cost 
of  such  works  may  be  gained  from  the  following  table  of 
prices  paid  during  the  year  1873,  within  the  direct  know- 
ledge of  the  writer. 

51.  For  sinking  shafts  in  soft  "killas"  or  clay  ground. 

Near  the  surface,        .        .        .  £2  to  £3  per  cubic  fathom. 
Below  about  20  fathoms,    .         .    3  to    4        ,,  ,, 

Sinking  shafts  in  " compact  killas,"  or  "pick  and  gad" 
ground. 

Near  the  surface,       .        .        .  £4  to  £6  per  cubic  fathom. 
Below  20  fathoms,     .        .        .     5  to    8        „  ,, 

Sinking  shafts  in  "  fair  blasting  ground." 

Near  the  surface,       .        .        .  £6  to  £20  per  cubic  fathom. 
Below  20  fathoms,     .         .         .     10  to    SO      ,,  ,, 

Levels  about  one-third  cheaper  for  non-blasting,  and 
one-half  cheaper  for  blasting  ground. 

In  extreme  cases  much  higher  prices  have  been  paid, 
but  these  will  suffice  for  the  elementary  student. 

The  shafts  referred  to  varied  from  8x6  to  12x9  feet, 
the  levels  from  6J  x  2J  to  7  x  5.  For  more  easy  com- 
parison the  prices  have  been  calculated  to  cubic  instead 
of  lineal  fathoms. 

Although  large  levels  are,  as  a  rule,  to  be  recommended, 
in  general  there  are  cases  in  which  very  small  levels  may 


43  PRINCIPLES  OP  METAL  MINING. 

be  adopted  with  advantage.  Thus,  in  the  china  clay  dis- 
tricts of  the  centre  of  Cornwall,  levels  only  4'  or  5'  high, 
and  2'0''to  2'  6"  wide  are  occasionallyjdriven  in  easy  ground 
to  explore  the  character  of  a  bed  of  clay,  or  to  serve  as 
channels  for  water.  When  the  ground  is  favourable,  these 
small  levels  will  often  stand  without  any  timber;  and  as 
they  are  not  used  for  the  transit  of  material  after  their 
completion,  their  small  size  is  no  disadvantage,  while 
their  economy  of  cost,  as  compared  with  larger  levels,  is 
very  considerable.  When  the  excavated  material  has 
not  to  be  wheeled  more  than  about  100  or  150  yards, 
such  levels  may  often  be  driven  at  a  total  cost  of  from 
8s.  to  12s.  per  lineal  fathom. 

52.  The  timber  used  in  Cornish  mines  is  mostly  Nor- 
wegian pine,  and  this  costs,  by  the  time  it  reaches  the 
mines,  about  Is.  per  cubic  foot  on  an  average.  Suppos- 
ing a  shaft,  therefore,  10  feet  by  7  feet,  inside  measure- 
ment, to  be  fully  timbered  by  the  "  sets  and  laths"  mode, 
using  timbers  of  about  9  inches  thick  for  the  sets,  which 
are  placed  4  feet  apart,  and  laths  of  1 J  inches  thick,  the 
cost  for  timber  will  be  about  £3, 10s.  per  fathom  of  depth, 
including  the  cost  of  cutting  out  the  timbers,  and  allow- 
ing for  a  little  waste. 

Such  timbers  in  a  shaft  of  the  size  specified  would  be 
suitable  for  soft  and  moderately  heavy  ground.  The  cost 
of  sinking  in  such  ground  would  be  from  £6  to  £8  per 
fathom.  The  cost  of  the  timbering  would  therefore  be 
about  one-half  the  labour  cost. 

For  a  level  in  similar  ground  7  feet  high,  3  feet  6 
inches  in  the  "cap,"  and  4  feet  6  inches  at  bottom, 
timbered  with  half-timber  sets,  and  1 J  laths,  the  cost  of 
driving  will  be  about  £2,  10s.  to  £3,  and  of  timbering, 
£1,  5s.  to  £1,  10s.,  or  again  about  half. 


PRODUCTIVE  WORK   IN  VEIN  MINING.  43 

CHAPTER  VII. 

PRODUCTIVE   WORK   IN   VEIN   MINING. 

53.  IN  a  well  managed  mine  the  deadwork  will  be  kept 
well  in  advance  of  the  stopes  which  yield  the  bulk  of  the 
ore.     It  is  true  that  as  the  levels  are  usually  driven,  and 
the  winzes  sunk  on  the  lode,  or  close  to  its  foot-wall,  some 
ore  will  be  obtained,  in  most  cases,  during  the  progress 
of  these  works.     Sometimes,  indeed,  the  ore  so  obtained 
is  more  than  sufficient  to  pay  all  the  expense  of  such 
drivages.     The  bulk  of  the  ore,  however,  is  got  out  by 
the  process  of  "stoping"  between  the  levels  in  those  por- 
tions which  are  judged  sufficiently  rich,  that  is,  in  the 
"bunches,"  or   "shoots"  of  ore.     Even  in  the   richest 
mines  these  portions  will  form  a  comparatively  small 
portion  of  the  lode,  and  in  poor  mines  the  "  bunches,"  as 
they  are  called,  are  few  and  far  between. 

54.  Two  totally  different  modes  of  stoping  are  in  common 
use,  called  respectively  "overhand"  and  "underhand" 
stoping. 

In  underhand  stoping  the  ore  is  gradually  worked  away 
downwards  from  the  floor  of  one  level,  the  ore  and  deads 
being  taken  out  through  the  level  next  below.  This 
mode  is  illustrated  in  fig.  19.  It  is  still  adopted  in  some 
German,  a  few  English,  and  many  South  American 
mines. 

In  the  mines  of  Cornwall,  underhand  stoping  has  been 
mostly  superseded  by  the  more  economical  overhand  mode. 
The  ore  is  thus  broken  more  cheaply,  but  more  timber  is 
required  for  the  construction  of  platforms,  upon  which 
the  men  stand  while  at  work,  "  stulls"  as  they  are  called. 
Usually,  some  at  least  of  this  timber  is  left  to  support  the 
hanging  wall  of  the  lode,  but  sometimes  it  will  stand  of 
itself  after  the  ore  is  worked  out,  or  stuff  may  be  brought 


44 


PRINCIPLES   OP   METAL   MINING. 


from  the  surface  to  fill  in  the  vacant  spaces  or  "  gunnies." 
Occasionally,  where  the  ore  is  not  wanted  immediately, 
much  of  it  is  left  in  the  level  for  a  time,  to  serve  as  a 
platform  for  the  men  while  breaking  away  the  ore  in  the 
"  backs."  Both  modifications  are  shown  in  fisr.  20. 


Fig.  19. — UNDERHAND  STOPING. 


Fig.  20. — OVERHAND  STOPING.  At  a  men  are  working  on  a 
staging  or  "  stull" ;  at  6,  men  are  at  work  standing  on  a  pile 
of  broken  ore;  c,  c,  are  the  ends;  d  is  a  "winze." 

Sometimes  the  stopes  are  worked  at  a  fixed  rate  per 
ton.  This  is  a  form  of  "  tutwork,"  but  it  is  sometimes 
called  simply  "stoping."  In  fair  blasting  ground  the 
prices  of  stoping  vary  in  Cornwall  from  2s.  Gd.  to  5s.,  or 


PRODUCTIVE    WORK   IN   VEIN   MINING.  45 

6s,  per  ton.     In  Somersetshire  and  South  "Wales  the 
prices  paid  will  be  considerably  higher. 

55.  Tribute  Work. — Very  often  certain  portions  of  the 
stopes  are  set  to  parties  (called  "pares")  of  "tributers," 
who  engage  to  break  the  ore,  and  in  some  cases  to  pay 
all  charges  until  it  is  ready  for  sale,  for  a  certain  propor- 
tion  of  its  value,   varying   from  a  few  pence   in  rich 
"pitches,"  to  15s.  in  the  £  in  poor  pitches.     A  species 
of  bidding  takes  place  at  "  setting  day"  for  all  the  pitches 
in  the  mine,  both  tutwork  and  tribute,  and   they  are 
"  set"  to  the  lowest  bidder,  as  a  matter  of  course. 

The  tributers  are  generally  the  most  skilful  miners,  and 
many  valuable  discoveries  have  been  made  by  them. 

56.  The  ore  broken  from  the  stopes  and  tribute  pitches 
is  wheeled  or  trammed  along  the  levels  to  the  shaft,  and 
raised  by  appropriate  machinery  to  the  surface,  as  will 
be  described  in  a  future  chapter. 

The  mode  of  driving  and  sinking  by  "  tutwork  "  at  a 
fixed  rate  per  fathom  works  well,  and  it  is  very  doubtful 
whether  any  better  mode  can  be  devised. 

In  poor  stopes,  where  large  quantities  of  ore  of  toler- 
ably even  quality  have  to  be  removed,  payment  at  a  fixed 
rate  per  ton  is  probably  the  best  mode,  the  men  being 
paid  only  for  the  merchantable  ore  sent  to  the  surface. 

Where  the  stuff  varies  much  in  quality,  the  mode  of 
tributing  will  probably  be  the  best,  although  it  is  a  good 
deal  gone  out  of  use  of  late. 

By  this  mode,  as  the  men  are  paid  a  certain  proportion 
on  the  value  of  the  ore  broken,  it  will  be  to  their  interest 
to  separate  the  deads  or  the  poor  stuff  from  best  work,  as  by 
long  experience  it  is  shown  that  the  aggregate  result  will 
be  to  the  advantage  of  the  men  when  such  a  selection  is 
made. 

57.  All  the  various  modes  of  working  require  the  most 
strict  watchfulness  and  much  judgment  on  the  part  of 
the  captain  or  overlooker. 

Tutwork  men  are  continually  allowing  the  shafts  and 
levels  to  become  crooked  and  small,  the  bottoms  of  the 


46  PRINCIPLES   OP  METAL  MINING. 

levels  to  rise  too  rapidly,  putting  in  faulty  timbering, 
etc. 

Stopers  paid  at  per  ton  are  always  apt  to  send  worthless 
material  to  the  surface  to  increase  their  total  yield.  Tri- 
buters  are  likely  to  leave  small  portions  of  rich  ore  behind, 
or  to  bury  it  up  with  deads,  where  it  would  pay  them 
better  to  break  down  ore  in  bulk.  For  these  and  other 
reasons,  a  captain  needs  to  be  continually  on  the  watch, 
to  visit  every  end  and  every  stope  continually,  and  to  be 
aware  of  every  change  of  ground  as  it  occurs.  He  must 
also  know,  from  practical  experience,  the  amount  of  work 
which  can  be  done  in  different  kinds  of  ground,  and 
accordingly  underground  captains  are  always  most  wisely 
selected  from  among  those  who  have  had  experience  as 
working  miners. 


CHAPTER  VIII. 

THE  MINING  OF  BEDS  AND  IRREGULAR  DEPOSITS. 

58.  THE  mineral  deposits  known  as    "  pipe  -veins/' 
"  gash-veins,"  "  carbonas,"  "  pockets,"  and   "  flats"  are 
often  of  considerable  importance,  but  less  so  than  the  true 
"rake- veins"  or  lodes.     Besides  these,  very  important 
"  beds"  of  ore  occur  in  many  districts  lying  parallel  to 
the  general  stratification  of  the  containing  rocks. 

Beds  of  iron  ore  of  considerable  thickness  occur  inter- 
stratified  with  beds  of  limestone  and  sandstone  in  the 
coal  measures  of  the  North  of  England,  and  in  the  oolitic 
rocks  of  Yorkshire  and  Northamptonshire.  Beds  of 
gravel  containing  particles  of  gold  or  of  tin  ore  occur  in 
the  valleys  of  very  many  countries  overlaid  by  superficial 
accumulations  of  alluvial  matter.  -* 

59.  The  mode  of  working  such  beds  differs  much  from 
that  followed  in  the  case  of  lodes,  and  must  be  here 
described.     As  types  of  such  workings  we  shall  briefly 


BED   MINING.  47 

explain  the  systems  of  working  followed  in  the  iron 
districts  of  Cleveland  in  Yorkshire,  and  in  the  tin-bearing 
gravels  of  Carnon  Valley  in  Cornwall. 

In  vein  mining  trial  borings  are  not  often  made,  shallow 
trial  pits  being  much  cheaper,  and  generally  being  found 
sufficient. 

In  bed-mining,  however,  the  system  is — most  properly 
— exceedingly  common.  These  trial-borings  are  made  as 
much  as  possible  in  a  direct  line  across  the  "  strike,"  or 
in  the  direction  of  the  "  dip"  of  the  rocks,  and  closer  to- 
gether in  disturbed  than  in  undisturbed  districts. 

60.  The  preliminary  examination  will  have  given  some 
information  as  to  the  depth  to  which  the  bore-holes  will 
need  to  be  carried.  Special  observations  must,  however, 
be  directed  to  discover  whether  any  "  faults,"  "  slips," 
"  throws,"  or  "  troubles"  exist  in  the  neighbourhood  of 
the  proposed  borings,  as  these  may  upset  all  calculations 
if  not  discovered  in  time.  In  some  cases  these  faults 
throw  the  beds  of  ore  down  many  fathoms,  as  shown  in 
fig.  21.  Generally,  if  one  such  fault  is  known  in  the 
district,  others  may  be  expected  to  occur  parallel  to  it. 


Fig.  21. — a,  a,  Bed  of  iron  ore;  &,  b,  fault;  c,  e',  e,  e',  bore- holes. 
The  greater  slips  in  the  North  of  England  coal  field,  for 
example,  have  more  or  less  an  east  and  west  direction; 
in  Lancashire,  north  and  south;  in  South  Wales,  north- 
west and  south-east.  Minor  slips  occur  in  almost  every 
direction,  and  one  object  of  the  trial  borings  is  to  deter- 
mine their  extent  and  position.  In  districts  known  to 


48  PRINCIPLES   OP   METAL  MINING. 

be  disturbed,  it  is  therefore  good  policy  to  have  very 
many  bore-holes,  as,  otherwise,  important  dislocations  of 
strata  may  not  be  discovered  until  much  money  has  been 
spent  in  laying  out  useless  or  unsuitable  works.  A 
consideration  of  fig.  21  will  show  that  the  information 
to  be  derived  from  bore-holes  may  be  seriously  misunder- 
stood if  they  be  not  sufficient  in  number.  Here  a  bed  of 
ore  a  a  a  is  thrown  by  an  unsuspected  fault  b  6.  It  is 
plain  that  if  bore-holes  are  only  made  at  c  c  the  bed  will 
be  supposed  to  have  the  inclination  shown  by  the  dotted 
lines  d  d,  but  if  the  additional  trials  at  e  e  be  made,  the 
true  position  of  the  beds  will  be  at  once  known. 


Fig.  22. — a,  b,  c,  d,  shafts;  e,e,  faults;  A,  B,  line  of  section  in  fig.  23. 

Figs.  22  and  23  show  a  series  of  faults  in  plan  and 
section — A  B,  fig.  23,  being  a  line  of  section  on  A  B, 
fig.  22.  The  metalliferous  miner  will  see  that  the  faults 
are  much  like  the  lodes  with  which  he  is  familiar,  differ- 
ing only  in  their  contents.  In  the  coal  measures  these 
faults  do  not  contain  ores  of  tin,  and  but  seldom  those  of 
copper,  but  they  frequently  yield  those  of  lead  or  iron. 
The  great  Minera  lead  vein  is  a  fault  which  differs  in 
no  essential  particular  from  the  faults  common  in  most 
bed-mining  districts. 

61.  Trial-Borings  are  usually  carried  out  by  contractors 


BED   MINING. 


49 


who  provide  their  own  skilled  workmen,  boring  tools,  and 
special  plant,  the  mine-owners  finding  engine  or  water- 
power,  and,  frequently,  labourers. 


Fig.  23. — Section  011  line  A,  B,  fig.  22  j  a,  b,  c,  d,  snafts;  e,e,  faults. 

The  boring  tools  are  sometimes  worked  simply  by  a 
rope  passed  over  a  shearlegs  or  triangle,  and  then  round  a 
"  jack-roll"  or  windlass,  but  for  deeper  holes  special  boring 
machines  have  been  invented,  among  which  "Kind's"  and 
"  Mather  and  Platt's"  hold  prominent  places.  The  boring 
tools  are  so  contrived  as  to  bring  up  from  time  to  time 
portions  of  the  bottom  for  examination.  To  prevent  the 
sides  of  the  hole  from  falling  in  it  is  often  necessary  to 
line  it  with  metal  tubes. 

62.  Cost  of  Boring. — The  cost  of  boring  at  Newcastle, 
in  1869,  was— 

For  the  first  five  fathoms, . 
,,     second        ,, 
third 


7s.  6d.  per  fathom. 
,       15s.  Od.          „ 
£1,  2s.  6d. 


and  so  on,  increasing  7s.  6d.  per  fathom  on  attaining 
each  complete  5  fathoms. 

ISu  D 


50  PRINCIPLES   OP   METAL   MINING. 

These  charges  were  for  boring  through  ordinary  sand- 
stone and  other  soft  rocks.  For  hard  limestone,  basalt, 
or  other  rocks  of  unusual  hardness,  or  for  holes  of 
unusual  depth,  special  agreements  are  made,  the  charges 
sometimes  amounting  to  many  pounds  per  foot.  The 
cost  of  such  bore-holes  is  very  great,  but  the  precision 
and  accuracy  thereby  secured  in  laying  out  permanent 
works  renders  it  well  worth  while  to  incur  the  expense. 

Major  Beaumont's  patent  Diamond  Borer  has  recently 
come  largely  into  use  for  trial  borings,  and  it  makes  its 
way  with  great  facility  through  every  kind  of  rock,  and 
in  very  many  cases  the  saving  of  time  and  money  result- 
ing from  its  employment  is  very  great.  All  bore-holes 
are  paid  for  according  to  the  depth,  the  portion  near  the 
surface  being  completed  at  a  much  less  cost  than  the 
deeper  portion.  Prices  for  boring  in  South  Wales,  in 
1873,  with  the  Diamond  Borer  were  as  follows : — 

In  the  lower  coal  measures  and  millstone  grit, 

For  the  first  100  feet,       .         .         9s.  6d.  per  foot. 
,,       second    ,,  .         .       13s.  6d.        ,, 

„      third       „  .        .       17s.  6d. 

and  so  on,  increasing  4s.  per  foot  after  attaining  each  100 
feet.  These  prices  are  for  bringing  up  a  1"  core.  Some 
additional  charges  are  made  for  fixing  head-gear,  etc. 

63.  Position  of  Shaft. — Having  at  length  determined 
the  depth  and  dip  of  the  ore  bed,  the  miner  will  be  in  a 
position  to  lay  out  his  principal  shaft  or  shafts.  "When 
the  ore  lies  as  in  fig.  21,  the  shafts  would  be  better  sunk 
at  c  e  than  c  e.  These  positions  are  chosen  in  order  that 
the  ores  may  descend  to  the  bottom  of  the  shaft  by  their 
own  weight,  to  save  the  expense  of  horse  or  engine 
power.  The  sinking  of  the  shaft  will  not  differ  much 
from  the  same  operation  in  metal  mining,  except  that  it 
will  sometimes  be  circular  instead  of  rectangular,  and 
always  vertical  instead  of  inclined.  In  bed  mining  for 
iron  ore  the  workings  will  seldom  be  very  deep,  except 
when  the  ore  is  worked  in  connection  with,  and  subor- 
dinate to,  the  working  of  coal,  so  that  ordinarily,  the 


BED   MINING. 


shafts  not  being  deep,  no  great  engineering  difficulties  are 
experienced  in  sinking  them. 


Fig.  24. — A  A,  BB,  Main  levels;  CC,  headways;  D,  regulating 
door;  E2E,  bords;  GG,  pillars;  H,  pack  wall  to  keep 
heading  open ;  c,  air  stoppings. 

For  shallow  workings,  where  the  ore  is  not  too  mnch 
hardened  by  a  great  weight  of  rock  above,  the  mode 
adopted  many  years  ago  by  Mr.  Bewick  at  Grosmont  may 
be  recommended,  as  illustrated  in  fig.  24.  A  pair  of  levels 
A  A,  B  B  are  driven  into  the  hill  from  the  lowest  point 
attainable  towards  the  boundary  of  the  property.  These 
levels  may  be  about  6  feet  wide  and  8  feet  high.  From 
one  of  these  levels  headings  C  C  are  driven,  following  the 
principal  heads  or  "joints"  of  the  ore,  about  22  fathoms 
apart,  and  8  feet  wide:  of  course  the  angles  which  these 
headings  make  with  the  levels  will  vary  in  different 
mines.  From  these  headings  the  bords  E  E  are  opened 
from  4  to  6  fathoms  apart,  widening  out  as  they  leave  the 
heading,  so  dividing  the  ore  into  pillars  averaging  0 


52 


PKINCIPLES   OP   METAL   MINING. 


fathoms  by  40  fathoms.  These  are  occasionally  holed 
into  the  next  heading.  The  pillars  are  removed  by 
cutting  away  sometimes  the  end  towards  the  rise,  some- 
times the  middle  or  lower  end,  according  to  circumstances, 
timber  being  used  to  support  the  roof  while  the  men  are 
so  engaged.  Fig.  25  shows  one  mode  of  removing  pillars. 


-Pi 

i  JLJL  :  j:_j- 

Sis.  \    ui\ 

Fig.  25. — SHOWING  MODE  OF  REMOVING  PILLARS  IN  IKON 
MINING. 

With  skilful  workmen  and  a  favourable  roof  very  little 
danger  is  to  be  apprehended,  and  very  little  timber  will 
be  lost. 

64.  In   deeper   workings    it   is   desirable,    from    the 
greater  compactness  of   the  ore,  to  lessen  the  propor- 
tions of   "  narrow  work,"  as   the   headings   are   called, 
leaving  the  pillars  much  larger,  or  else  clearing  a  long 
face  of  work  at  one  and  the  same  time,  as  will  be  more 
fully  described  in  the  treatise  on  coal  mining. 

The  cost  of  getting  ore  will  vary  according  to  the 
thickness  of  the  bed,  the  hardness  or  compactness  of  the 
ore,  and  other  particulars,  from  Is.  to  2s.  6d.  per  ton  in 
the  headings,  and  from  9d.  to  Is.  6d.  per  ton  from  the 
pillars.  Very  often  the  headings  are  driven  at  an  agreed 
price  per  fathom  in  length,  which  may  vary  from  £1  to  £3 
per  fathom,  exclusive  of  the  cost  of  timber  and  haulage. 

65.  Alluvial  Mining1. — In  working  alluvial  beds,  which 
are  too  deeply  situated  to  be  worked  in  the  open  as  des- 
cribed in  the  next  chapter,  a  kind  of  bed  mining  very 


ALLUVIAL   MlXlKCt.  53 

similar  to  that  just  described  is  frequently  adopted. 
Shafts  are  sunk  until  the  ore-ground  is  reached;  levels 
are  driven  for  the  most  part  in  the  orey  stratum,  and 
supported  by  timber;  the  ore  is  gradually  worked  away, 
the  timber  withdrawn,  and  the  roof  allowed  to  subside. 

When  the  ore-ground  lies  near  the  surface,  and  the 
ground  above  is  dry,  but  little  difficulty  is  experienced; 
but  if  the  overburden  is  thick  and  wet,  and  especially  if 
the  ore-ground  should  pass  under  the  bed  of  a  stream  or 
under  the  sea,  the  work  is  often  one  of  great  difficulty. 

At  the  E-estronguet  Tin  Stream  Works  in  Cornwall,  a 
bed  of  tin-bearing  gravel  occurs  under  a  creek  of  Falmouth 
Harbour,  beneath  about  10  feet  of  water  at  low  tide,  and 
about  60  feet  of  mud.  This  mud  is  covered  at  high  water 
with  about  20  feet  of  water. 

66.  Trial  borings  were  in  the  first  instance  made  3 
inches  diameter,  by  which  the  thickness  and  quality  of 
the  tin  gravel  were  approximately  determined.     A  shaft 
was  then  sunk  on  the  shore  to  a  depth  of  18  fathoms,  and 
from  this  a  deep  level  was  driven  towards  and  under 
another  shaft  which  was  made  of  iron,  and  sunk  in  the 
bed  of  the  estuary.     A  tramroad  was  then  laid  in  this 
level  2|-  feet  above  its  floor,  by  which  the  ore  was  brought 
out.    The  space  underneath  serves  as  a  water  channel 
and  standage  or  sump. 

67.  The  iron  shaft  consists  of  cylinders  of  cast  iron  6 
feet  diameter,  6  feet  long,   and  1J  inches   thick,  with 
internal  flanges  faced  in  a  lathe.     Each  length  weighed 
2|-  tons,  and  was  lowered  by  a  crane  through  an  opening 
in  a  timber  stage  between  guides  to  its  true  position. 
The  bottom  length  was  made  sharp,  and  weights  were 
placed  on   the   upper   lengths   until   the   true   bed  was 
reached — the   greatest   weight   at   any  one   time   being 
250  tons. 

The  shaft  is  continued  through  and  below  the  tin 
bed  as  a  timbered  excavation — leaving  two  openings 
opposite  each  other.  A  level  is  driven  from  these,  bearing 
north-east  and  south-west,  to  prove  the  extent  of  the  tin 


54  PRINCIPLES  OF  METAL  MINING, 

bed.  From  these  two  other  levels  are  driven  up  the 
creek  in  a  north-westerly  direction — as  shown  at  E  E 
in  fig.  26,  which  is  a  plan  and  section  of  the  workings — 
each  having  a  tramroad  laid  in  it.  Air  levels  are  driven 
at  right  angles  to  these  as  far  as  the  tin  bed  is  productive. 
The  ore  is  got  out  by  a  kind  of  long-wall  method  called 
"  stripping,"  at  J  J — wheeled  back  to  the  main  levels — 
trained  to  the  "  passes"  F  F,  communicating  with  the 
deep  level  A  A,  where  it  is  shot  into  the  waggons  waiting 
below  to  receive  it.  Thence  it  is  conveyed  to  the  bottom 
of  the  land  shaft  and  raised  in  cages  to  the  surface. 

68.  The  tin  gravel  varies  in  thickness  from  3  inches  to 
7  feet,  averaging,  perhaps,  5  feet;  the  produce  in  oxide  of 
tin  varying  from  1 5  per  cent,  to  *1  per  cent.  All  the 
levels  need  strong  timbering  to  resist  the  crush  of  the 
overlying  mud.  In  the  principal  levels  this  consists  of 
"  sets"  of  Norway  timber  8"  thick  for  the  legs  and  10"  in 
the  cap.  These  legs  are  4  J  feet  apart  at  bottom,  7  feet  long, 
and  2J  feet  apart  at  top.  The  sets  are  placed  every  2J 
feet  in  the  level,  and  covered  in  with  "  half-timbers"  over 
the  caps,  and  "laths"  i \  inches  thick  at  the  sides.  The  cost 
of  driving  the  main  levels  is  about  £3  to  £5  per  fathom. 
The  tin  gravel  is  "stripped"  at  a  cost  of  3s.  to  6s.  per  ton. 

A  width  of  30  feet  of  gravel  is  left  on  each  side  of  the 
main  levels  to  keep  them  open. 

The  working  of  irregular  deposits  of  ore  varies  much 
in  different  districts,  but  all  the  modes  are  modifications 
of  the  systems  employed  in  vein  mining  and  bed  mining, 
so  that  no  special  description  is  necessary 


CHAPTER  IX. 

ON  OPEN  WORKS  AND  HYDRAULIC  MINING. 

69.  IN    most    mining    countries,   and    especially    in 
countries  yielding  tin  ore  and  gold,  these  minerals  are 


OPEN  WORKING: 


55 


found  not  only  in  veins  or  deposits,  but  also  as  small 
pebbles  or  grains  scattered  through  the  detrital  matter  or 
alluvium  which  occupies  the  valleys.  Such  alluvium  also 
contains  diamonds  and  other  precious  stones  in  Brazil  and 
South  Africa,  where  the  mode  of  working  adopted  is  very 
similar  to  that  by  which  the  stream  tin  or  alluvial  gold  are 
obtained.  The  deposit  of  tin  gravel  at  the  mouth  of  the 
Carnon  Valley  is  illustrated  in  fig.  26,  but  the  overlying 
mud,  and  the  situation  in  a  creek  of  Falmouth  Harbour, 
make  it  necessary  to  work  it  here  by  mining,  as  described 
in  the  last  chapter.  The  same  deposit,  however,  higher 
up  the  valley,  as  well  as  many  similar  ones,  have  been 
frequently  worked  in  the  open  by  removing  the  over- 
burden entirely,  so  laying  bare  the  tin  ground. 


Fig.  26.— A,  A,  deep  level;  E,  E,  air  levels;  D,  iron  shaft;  C,  land 
shaft;  H,  stripping  levels;  F,  F,  "passes"  to  deep  level. 

70,  Mode  of  Working. — The  most  advantageous  mode 
of  working  is  to  clear  the  over-burden  away  completely 
from  a  good  sized  space,  remove  the  ore-ground  for  sub- 
sequent treatment,  or  treat  it  on  the  spot,  and  then  to 
fill  up  the  space  with .  the  over-burden  from  the  next 
section.  In  this  manner  no  part  of  the  over-burden 
has  to  be  removed  to  a  great  distance,  nor  yet  to  be 


66  PRINCIPLES   OP  METAL  MINING. 

lifted  to  any  considerable  height;  and  the  cost  of  removal 
will  lie  between  2s.  and  5s.  per  cubic  fathom.  Even  coal 
is  sometimes  thus  obtained  from  open  workings  in  South 
Wales,  where  they  are  called  "  patch"  works. 

71.  Hydraulic  Mining. — In  California,  Nevada,  and 
elsewhere,  very  large  deposits  of  sandstone  rock  occur 
which  contain  a  small  but  paying  proportion  of  gold. 
These  rocks  are  sometimes  hard,  and  need  to  be  stamped 
to  a  fine  powder  before  the  gold  or  tin  ore  can  be 
extracted,  but  often  they  are  so  far  decomposed  that 
they  may  be  washed  down  by  a  jet  of  water  directed 
with  force  upon  the  face.  The  water  is  stored  in  re- 
servoirs at  a  considerable  elevation,  and  brought  to  the 
works  in  flumes  from  great  distances.  In  this  manner 
a  pressure  of  100  to  200  Ibs.  per  square  inch  is  often 
obtainable,  and  with  such  a  jet  from  a  12"  to  20"  pipe,  and 
a  nozzle  from  4"  to  8",  a  man  is  able  to  wash  down  the 
rock  at  a  cost  of  from  Id.  to  2d.  per  ton.  The  same  water 
serves  for  the  subsequent  dressing  operations,  and  the  total 
working  cost  is  so  slight  that  stuff  containing  no  more 
than  fourpenny  worth  of  gold  per  ton  is,  when  soft,  work- 
able at  a  profit.  This  is  the  so-called  hydraulic  mining. 

In  Cornwall  a  good  deal  of  tin  ore  is  obtained 
from  both  the  granite  and  slate,  especially  in  the  centre 
of  the  county,  by  open  working.  A  produce  of  from 
3  Ibs.  to  9  Ibs.  of  saleable  tin  ore  per  ton  of  stuff  is 
found  sufficient  to  pay  all  expenses  and  to  leave  a  con- 
siderable profit,  and,  under  favourable  circumstances,  the 
author  has  known  2  Ibs.  per  ton  to  yield  a  profit.  The 
oxide  of  tin  occurs  in  the  joints  of  the  rocks  in  very  thin 
layers,  and  it  is  necessary  to  break  down  the  rock  and 
crush  and  "  dress "  it  en  masse  in  order  to  obtain  the 
"  black  tin."  At  Minear  Downs,  near  St.  Austell,  the 
ore  occurs  in  a  soft  killas,  and  one  man  is  able  to  break 
down  from  7  to  8  tons  per  day;  at  Mulberry  Hill,  near 
Bodmin,  which  is  also  killas,  from  5  to  6  tons.  Nearly  all 
the  work  in  these  two  places  is  effected  by  the  pick  and 
gad — blasting  being  rarely  necessary.  At  Rock  Tin  Mine, 


OPEN  WORKINGS.  57 

near  St.  Austell,  a  large  open  quarry  is  worked  for  tin  in 
a  very  hard  schorlaceous  rock.  Here  the  average  produce 
is  about  8  to  9  Ibs.  per  ton  of  stuff,  and  each  man  can 
break  down  from  1 1-  to  2  tons  per  day.  The  rock  in  this 
quarry  requires  frequent  blasting. 

72.  China  Clay. — In  very  many  parts  of  Cornwall,  and 
in  Devonshire,  a  peculiar  kind  of  white  granite  is  so  com- 
pletely decomposed  as  to  be  quite  soft,  the  felspar  being 
converted  into  kaolin  or  China  clay.    A  common  mode  of 
working  this  is  to  bring  a  stream  of  water  over  the  face, 
which  is  guided  hither  and  thither  by  a  man  who  uses  a 
pick  to  assist  the  water  in  bringing  down  the  rock.    In  this 
manner  one  man  can  often  bring  down  from  12  to  20 
tons  of  rock  per  day.     It  is  probable  that  the  use  of 
a  powerful  jet  as  described  above  would  enable  him  to 
double  these  quantities  at  least. 

73.  For  all  these  operations  it  is  necessary  to  remove 
the  "  over-burden."     The  circumstances  of  working  will 
vary  much  in  different  works.  On  a  hill  side  the  burden  may 
be  removed  cheaper  than  on  level  ground — a  deep  over- 
burden cheaper  in  proportion  to  its  depth  than  a  shallow 
one,  etc.     Sometimes  the  over-burden  will  be  so  soft  and 
regular  in  composition  that  a  pick  is  hardly  necessary, 
at  others  it  will  be  very  hard  and  firm,  or  mingled  with 
stones,  large  and  small,  and  all  these  circumstances  will 
affect  the  cost  of  removal.     In  general,  however,  if  the 
stuff  may  be  stored  at  moderate  distances  without  being 
much  raised,  and  if  proper  tramroads  be  provided,  the 
cost  will  not  be  likely  to  fall  under  2s.  nor  to  exceed  5s. 
per  cubic  fathom.     In  cases,  however,  where  large  rocks 
occur  which  need  to  be  blasted,  the  cost  of  blasting  must 
be  added. 

74.  Blasting. — The  process  of  blasting  deserves  careful 
study   from   every   one  engaged  in   mining   operations, 
whether  in  open  works  or  underground.     It  is,  of  course, 
to  be  learnt  by  practice   only,   but   some  few   general 
remarks  will  no  doubt  be  useful.     The  process  in  outline 
is  as  follows : — A  hole  is  first  made  in  the  rock  by  means 


58  PRINCIPLES  OP  METAL  MINING, 

of  the  mallet  and  borer  (these  tools  will  be  described 
in  the  next  chapter).  In  general  one  man  holds  the 
borer  while  it  is  struck  or  "beaten"  by  one,  two,  or 
three  strikers,  who  deliver  heavy  blows  alternately  upon 
its  head,  the  holder  giving  it  about  one-eighth  of  a  turn 
after  every  blow.  A  little  water  is  fed  into  the  hole 
from  time  to  time,  and  at  intervals  the  "  sludge"  is  with- 
drawn from  the  hole  by  means  of  a  "  swab-stick."  In 
this  way  a  hole  is  bored  from  1  inch  to  2  inches  in 
diameter  at  the  rate  of  from  4  to  30  inches  per  hour, 
according  to  the  hardness  of  the  rock.  In  the  extreme 
west  of  Cornwall,  at  St.  Just,  a  small  borer  is  used  which 
is  held  in  the  miner's  left  hand — the  thumb  and  little 
finger  below,  the  other  fingers  above  the  borer — and 
struck  with  a  light  hammer  held  in  the  right  hand. 

In  quarry  work  a  "  jumper  "  is  occasionally  used,  but 
very  rarely  by  miners. 

Of  late  years  boring  machines,  working  by  steam  or  by 
compressed  air,  have  been  introduced  for  the  purpose 
of  boring  these  "shot-holes,"  as  they  are  termed,  but 
hitherto  they  have  not  proved  very  successful  under- 
ground, although  they  have  done  good  service  in  driving 
large  tunnels,  in  sinking  shafts,  and  in  open  quarry  work. 

The  hole  being  bored  to  its  proper  depth,  a  quantity  of 
gunpowder  is  placed  in  it, — a  piece  of  safety  fuse  long 
enough  to  reach  the  powder  is  placed  in  the  hole,  and  it 
is  filled  up  with  hard  clay,  sand,  broken  brick,  or  other 
tamping  material,  which  is  driven  in  firmly  with  the 
tamping  bar.  This  was  formerly  done  with  an  iron  bar, 
when  the  operation  was  very  dangerous,  but  it  is  illegal 
now  to  use  any  other  than  a  copper  or  copper-tipped  bar, 
and  accidents  while  tamping  are  of  comparatively  rare 
occurrence. 

75.  Sometimes  gun-cotton,  nitro-glycerine,  or  dynamite 
are  used  instead  of  gunpowder,  when  tamping  becomes 
less  necessary,  or  even  altogether  needless.  These  explo- 
sives are  especially  valuable  in  wet  places,  and  for  blasting 
loose  rocks. 


TOOLS  USED  IN  BREAKING  ROCK.  59 

76.  The  hole  having  been  charged,  the  outer  end  of  the 
fuse  is  set  on  fire,  the  workmen  retire  to  a  safe  place,  and, 
when  the  fire  reaches  the  powder  or  other  material  used,  it 
explodes  with  great  violence.    In  general,  the  holes  need 
not  be  so  large  nor  so  deep  for  dynamite,  gun-cotton,  or 
mtro-glycerine  as  for  gunpowder,  and  they  are  usually 
larger  in  open  workings  than  underground. 

77.  The  miner  should  so  place  his  hole  that  it  may 
encounter  as  nearly  as  possible  an  equal  resistance  in 
every   direction,   and  much    practice,    observation,   and 
judgment  will  be  needed  before  he  will  be  able  properly 
to  apportion  the  charge  to  the  amount  of  work  to  be 
done.     He  must  have  a  keen  eye  for  "  vughs,"  "joints," 
and  "  breast-heads."     In  some  cases  it  will  be  an  advan- 
tage to  introduce  the  powder  or  other  explosive  in  a  car- 
tridge form,  especially  in  wet  or  loose  ground. 


CHAPTER  X. 

OP  THE  TOOLS   USED   IN  BREAKING  ROCK. 

78.  THE  principal  tools  used  by  miners  in  "  breaking 
ground,"   as  it  is    termed,   are  pick-axes  or    "picks," 
"pikes,"   "hacks,"    "slitters,"   or  "mandrils,"  as  they 
are   variously   called,  of  different   kinds;    hammers   or 
"sledges,"   of    different    forms   and   weights;    shovels; 
wedges  or  "gads,"  and  "moyles;"  borers  or  "boryers." 

79.  Besides  these  we  may  mention  such  miscellaneous,1 
tools  as  "tamping bars,"  "prickers,"  "swab-sticks," hatchets 
or  "  dags,"  adzes,  saws,  and  other  tools  used  for  blasting, 
timbering,  and  other  special  purposes.     All  these  vary 
considerably  in  form,  size,  and  other  particulars  in  dif- 
ferent districts,  and  when  used  for  different  purposes, 
We  can  only  describe  here  the  principal  varieties. 

80.  Picks. — These  are   mostly  made  of   iron,   with 
points  or  "  tips  "  of  steel,  while  the  handle,  "  helve,"  or 


60  PRINCIPLES  OP  METAL  MINING. 

"  hilt "  is  formed  of  ash  or  hickory.  In  the  metal  mines 
of  the  West  of  England  the  picks  are  usually  of  the  form 
shown  in  fig.  27,  which  is  called  the  "poll-pick,"  having 
its  head  or  "pane"  a  steeled  as  well  as  its  point.  This 
is  the  most  useful  tool  the  miner  has,  as  it  serves  as  a 
hammer  as  well  as  a  pick.  It  is  also  very  much  used  as 
a  lever,  the  curve  of  the  pick  serving  as  a  fulcrum,  and 
great  leverage  being  obtained  through  the  handle  or 
"  hilt."  It  is  also  much  used  as  a  hammer  to  drive 
the  "  gad,"  an  instrument  presently  to  be  described.  A 
fair  length  is  about  15  inches,  the  weight  is  about  4  Ibs., 
but  they  are  made  occasionally  but  little  over  2  Ibs.,  and 
sometimes  as  much  as  7  Ibs.  or  even  10  Ibs.  The  heaviest 
picks  in  Cornwall  are  used  in  the  China  clay  pits  of  the 
centre  of  the  county. 

Picks  of  very  similar  form  are  used  in  the  lead  mines 
of  Derbyshire  and  Wales. 

When  the  pick  is  much  used  as  a  lever,  the  head  is 
frequently  formed  as  in  fig.  28a,  with  a  projecting  wing 
to  afford  increased  support  to  the  helve.  This  is  called 
a  jackass  pick.  Similar  support  is  better  afforded  by 
making  the  eye  portion  of  the  pick  somewhat  deeper 
than  usual. 

Ordinarily,  for  hard  ground,  the  point  is  sharpened 
four-square,  but  for  soft  ground  it  is  usually  flattened, 
and  for  clay  ground  it  is  frequently  spread  out  to  a  width 
of  U"  or  2",  as  in  fig.  286. 

Fig.  29  shows  a  form  of  pick  frequently  used  in  the 
iron  mines  of  Somerset  and  Wales,  weighing  from  4  to 
5  Ibs.  A  very  similar  form,  but  made  somewhat  slighter, 
and  weighing  only  2  or  3  Ibs.,  is  used  in  the  coal  mines 
of  South  Wales.  For  sinking  purposes  they  are  made 
much  heavier,  often  7  Ibs.,  when  they  are  known  as 
"  hacks"  in  some  parts.  These  are  often  18  to  22  inches 
long. 

Helves  of  picks  vary  from  24  inches  long  in  some  poll- 
picks  used  in  confined  places,  to  36  inches  or  more. 
Many  other  forms  of  pick  are  in  common  use,  almost 


TOOLS  USED  IN  BREAKING  ROCK.         61 

every  district  having  its  own  special  form.  The  cost  of 
a  poll-pick  of  4|  Ibs.  weight,  the  poll  and  tip  well  steeled, 
is  in  Cornwall  at  present  about  2s.  6d.;  the  cost  of  the 
helve  or  "  hilt"  is  4d.  J 

81.  Hammers. — The  chief  kinds  used  in  metal  mines 
are  mallets  or  "malls,"  used  for  "beating  the  borer;" 
"  sledges,"  for  breaking  up  large  masses  of  rock,  and  for 
driving  the  "gad;"  and  "cobbing"  and  "  spalling  ham- 
mers" for  further  reducing  the  ore;  "lath  sledges"  are 
used  for  driving  the  laths  in  ground  requiring  timbering. 

The  head  or  "pane"  is  usually  steeled,  the  handle  or 
"hilt"  is  made  of  ash  or  hickory.  The  "eye  "is  occa- 
sionally round,  sometimes  square,  more  usually,  and  much 
better,  oval.  Fig.  30  represents  the  "  cat-head"  mallet, 
used  for  "  beating  the  borer"  in  many  parts  of  Cornwall. 
It  varies  in  weight  from  4  to  9  Ibs. — averaging,  perhaps, 
6  Ibs.  or  7  Ibs.  Fig.  31  is  a  "  bloat-head"  hammer  used 
for  single-handed  boring  in  the  extreme  west  of  England, 
at  St.  Just.  It  weighs  from  2J  to  4  Ibs.  The  hilts  of 
these  single-handed  boring  hammers  are  rarely  so  much 
as  IS"  long,  but  those  for  double-handed  hammers  are 
from  24  inches  to  30  inches  in  length. 

These  boring  sledges  are  sometimes  used  for  driving 
wedges  or  "  gads,"  and  the  poll-pick  is  also  largely  used 
for  this  purpose.  Sometimes  a  special  "  gad  sledge"  is 
provided  for  the  purpose.  It  is  much  like  that  already 
figured,  but  longer  in  the  head  and  narrower  in  the  pane, 
and  weighs  about  7  or  8  Ibs.  The  form  shown  in  fig.  32 
is  used  for  breaking  up  large  rocks,  but  in  this  case  the 
weight  is  often  increased  to  15  Ibs.,  20  Ibs.,  or  even 
more.  These  are  sometimes  called  lump  sledges. 

Fig.  33  represents  a  "  lath-sledge,"  for  driving  the 
"  laths"  used  in  timbering  tender  ground  in  Cornwall 
and  elsewhere. 

Fig.  34  shows  a  "  spalling  hammer"  in  common  use, 
the  weight  will  be  from  3  to  6  Ibs. 

82.  Shovels  or  Spades. — These  also  vary  much  in  form 
size,     Fig.  35  represents  the  long-handled  shovel, 


62  PRINCIPLES   OF   METAL   MINING. 

used  almost  universally  throughout  the  west  of  England 
not  only  for  removing  loose  material  underground,  but 
also  for  general  use  at  the  surface.  The  "  plate"  is  from 
8  inches  to  12  inches  wide,  and  10  to  15  inches  long, 
slightly  hollowed,  and  strengthened  with  a  central  rib 
extending  about  half  way  down.  The  point  is  often,  and 
with  great  advantage,  steeled.  The  handle  or  "  hilt"  is 
from  1  to  5  feet  long  in  general,  slightly  curved.  The 
weight  of  the  plate  is  from  3  to  4  Ibs;  the  cost,  un- 
steeled,  from  2s.  to  3s.,  steeling  about  6d.  extra. 

A  shovel  like  fig.  36  is  much  used  in  the  iron  mines 
of  the  North  of  England. 

The  proper  use  of  the  long-handled  shovel  of  the  West  of 
England  is  not  very  easily  acquired;  nor  is  it,  perhaps,  so 
well  adapted  for  removing  very  light  and  loose  material 
as  the  shorter  handled  shovels.  For  rough  and  coarse 
materials,  however,  its  value  cannot  be  over-estimated,  as 
the  point  makes  its  way  readily  beneath  or  between  the 
masses,  and  the  knee  serves  as  a  fulcrum  at  the  same  time 
for  the  long  lever  handle. 

The  vanning  shovel,  used  in  "  vanning"  tin  and  other 
ores,  is  somewhat  like  fig.  35,  but  larger,  rounded  at  the 
ends,  and  without  the  strengthening  rib.  It  is  made  of 
very  thin  iron,  s"o  as  not  to  exceed  2  or  2  J  Ibs.  in  weight. 
The  plate  may  be  about  15"  long;  the  handle  about  3 
feet.  Much  attention  is  paid  so  as  to  secure  a  proper 
curve  for  both  plate  and  handle,  as  much  of  the  success  of 
the  operation  depends  upon  these  particulars. 

83.  Wedges. — These  are  largely  used  for  breaking 
down  portions  of  rock,  being  driven  by  the  poll-picks  or 
hammers  already  mentioned.  In  Cornwall  the  wedges 
most  commonly  used  are  known  as  "  gads,"  "  pickers," 
and  "  moyles"  or  mules.  The  gads  are  usually  made  of 
steel,  vary  from  6  inches  to  10  inches  in  length,  and 
weigh  from  1  to  5  or  6  Ibs.  Fig.  36  shows  a  very  useful 
form.  The  pickers  used  in  the  Western  mines  are  longer 
and  narrower.  They  are  used,  as  the  name  implies,  to 
pick  out  the  small  fragments  of  loo(se  rock  which  wedge 


TOOLS  USED  IN  BREAKING  ROCK.         63 


Fig.  27. 


Fig.  31.       Fig.  32.     Fig.  33. 


Fig.  35. 


Fig.  3G.F]g-  37. 


0 


Fig,  33.   Fig.  39.  Fig.  40. 


64  PRINCIPLES   OP   METAL   MINING. 

iii  larger  portions  in  some  situations.  Worn  out  steel 
borers  make  excellent  gads  and  pickers. 

In  Saxony  it  is  common  to  make  the  gads  with  an  eye 
in  the  centre,  as  shown  in  fig.  37.  The  miner  passes  a 
string  through  the  holes,  and  so  carries  a  day's  supply 
without  inconvenience.  The  larger  kinds  of  wedges 
known  in  Cornwall  as  "  inoyles"  are  used  more  especially 
in  quarry  work.  They  vary  from  10  inches  to  18  inches 
in  length,  and  weigh  from  7  to  20  Ibs.  They  are  some- 
times formed  of  iron  throughout,  but  preferably  with  a 
steel  tip.  The  term  gad  is  sometimes  restricted  to  those 
which  are  brought  to  a  point,  those  having  a  chisel  edge 
are  more  properly  termed  wedges.  The  cost  of  steel 
wedges  varies  much  from  time  to  time,  but  at  the  present 
time  is  about  8d.  per  Ib.  Iron  wedges  cost  rather  less 
than  half  this  amount.  *  ** "  - 

84.  Borers. — These  are  often  called  "  striking  borers," 
"drills,"  "bits,"  and  sometimes  "augurs."  Of  course  they 
are  very  different  to  true  augurs. 

Ordinary  borers  are  worked  by  percussion,  as  described 
on  page  58,  borers  which  revolve  under  pressure  are 
seldom  used  in  mining  operations,  except  for  deep  trial 
borings. 

The  borers  used  in  metal  mining  are  mostly  of  the 
form  shown  in  fig.  39,  varying  in  width  from  1J- 
inches  down  to  1  inch,  and  in  length  from  1  foot  to  4 
feetj — the  shorter  being  wider  than  the  longer  ones,  in 
order  to  afford  "  clearance"  as  they  succeed  each  other  in 
boring  deep  holes.  In  open  quarry  work  much  longer 
and  larger  borers  are  used.  In  the  west  of  Cornwall,  at 
St.  Just,  the  borers  are  lighter  and  smaller  than  else- 
where, single-handed  boring  being  common  as  already 
mentioned.  The  best  borers  are  made  of  steel  throughout, 
but  sometimes  iron  borers  with  steel  tips  are  still  used. 
For  boring  machines,  the  form  of  the  cutting  edge  is  very 
different  from  that  shown  in  the  figure — the  chief  forms 
being  the  "  Z"  and  the  "  X."  The  jumper  shown  in  fig. 
40  is  used  in  open  quarry  work,  but  not  often  by  miners, 


DEAD   WORK   IN   SHAFTS.  65 

It  is  sharpened  and  steeled  at  both  ends,  and  is  held  by 
the  lump  in  the  middle. 

85.  Miscellaneous  Tools. — The  tamping  bar  is  a  bar 
of  iron  tipped  with  copper,  or  a  rod  of  hard  wood,  used 
for  ramming  home  a  "tamping"  of  clay  or  earthy  material 
so  as  to  confine  the  gunpowder  or  other  explosive  in  a 
bore-hole  to  increase  its  useful  effect.  The  pricker  was 
formerly  much  used  to  make  a  hole  through  the  tamping, 
but  since  the  invention  of  safety  fuse  it  has  gone  very 
generally  out  of  use,  the  tamping  being  now  rammed 
around  the  fuse  itself. 

Swab-sticks  are  rods  of  wood,  with  the  fibres  of  the  end 
beaten  loose,  used  for  drawing  wet  mud  or  sludge  out  of  a 
bore-hole.  Sometimes  a  kind  of  syringe  known  as  a  gun 
is  used  with  good  effect  for  this  purpose. 

A  hatchet  or  "  dag"  is  very  useful  in  preparing  timber 
for  tender  ground,  and  in  Cornwall  the  miners  are  expected 
to  be  expert  in  its  use,  and  also  in  the  use  of  a  cross-cut 
saw,  hand  saw,  adze,  and  augur. 


CHAPTER  XII. 

ON   DEAD   WORK   IN   SHAFTS,  ETC. 

86.  THE  shafts  for  metal  mines,  besides  the  actual 
labour  of  excavating,  require  much  additional  attention 
before   they  are  ready  for  daily  use.     Some  shafts  are 
intended  for  pumping  only;  some  for  pumping  and  rais- 
ing ore;  and  many  for  the  use  of  the  miners  in  proceeding 
to  and  from  their  work  in  addition  to  these  objects. 

87.  Protection  from  Danger. — As  the  shaft  reaches  a 
depth  of  10  to  20  fathoms,  it  is  usual — or  at  least  proper 
— to  protect  the  men  working  in  the  bottom  from  the 
danger    arising   from   the   occasional  fall   of   stones   or 
materials,  since   a  very  small  stone  falling  upwards  of 
GO  feet  is  sufficient  to  cause  death.      A  portion  of  the 

18B  E 


PRINCIPLES   OP  METAL   MINING. 


shaft  ig  covered  over  by  a  temporary   sloping   roof  o£ 
boards  called  a  "penthouse,"  as  shown  in  fig.  41,  and  the 
men   retire  beneath   this  when- 
ever anything  is  being  raised  or 
let  down  in  the  shaft. 

88.  Striking  Deals.— To  dimi- 
nish the  risk  of  accident  from  the 
upsetting  of  the  kibbles,  what  are 
known  as  "  striking  deals"  are 
used  in  some  places.     These  are 
pieces  of  wood  placed  as  shown  in 
fig.  41,  which  serve  to  guide  the 
ascending  kibble  through  the  open- 
ing at  the  top  of  the  shaft.    Fig. 
42  is  a  plan  of  a  shaft  divided  for 
pumping  and '  'winding,"  or  "draw- 
ing stuff,"  with  a  narrow  central 
division  for  a  ladder-way.     The 
winding  division  a  is  boarded  in 
entirely  from  the  ladder-way  b, 
but  the  portion  c,  containing  the 
pumps  dd,  is  only  separated  at 
intervals  from  the  ladder-way. 

89.  Ladders. — The  ladders  are 
usually  made  from  20  to  30  feet 
long.    The  * '  rungs  "  or  "  staves  " — 
preferably  10",  but  sometimes  12" 

Fig.  41.  apart — are  best  made  of  iron  bars 

let  into  the  wooden  sides,  as  shown  in  fig.  43.  At  the 
top  and  bottom,  and  at  intervals  throughout  the  length, 
longer  bars  cc  pass  quite  through  the  sides, 
and  are  secured  by  a  "  cotter"  as  at  d,  or 
by  a  nut  as  at  e. 

The  ladders  are  placed  in  the  shaft  as 
shown   in   figs.  44,  45,  of  which  fig.  44 
Fig.  42.        represents  the  safest  mode,  as   the   man- 
holes bb,    in  the  "  sollars"  aa,  are  under   the  ladders. 
When  the  ladders  are  placed  as  in  fig.  45,  a  careless  stepper 


DEAD   WORK   IN  SHAFTS. 


67 


may  step  back  into  the  man-hole,  and  losing  his  hold  011 
the  ladder,  may  "  fall  away."  Sometimes  the  man-holes 
are  protected  by  trap-doors,  but  this  leads  to  much  delay, 
BO  that  in  practice  they  are  seldom  kept  shut. 

90.  Partings. — The  partings  of  the  shafts  consist  of 
strong  beams  of  wood,  which  either  rest  upon  the  timber 
"  sets"  of  the  shaft,  or,  in  hard  ground,  are  let  into  the 
country  on  either  side;  longitudinal  timbers  are  nailed 
to  these  so  as  to  form  the  shaft  part- 
ing, and  the  same  cross  timbers  serve 

to  support  the  sollars. 

In  the  great  majority  of  the  Cornish 
metal  mines,  and  in  many  of  those  of 
South  Wales  and  the  North  of  Eng- 
land, the  men  go  to  and  from  their 
work  by  means  of  the  ladder-ways  just 
described.  The  going  down  is  not  very 
hard  work,  but,  as  the  average  daily 
amount  of  climbing  is,  perhaps,  from 
400  to  600  feet,  and  sometimes  as 
much  as  1500,  and  as  the  men  have 
frequently  to  bring  up  some  of  their 
tools  for  sharpening,  the  labour  becomes 
very  severe — as  much  in  some  instances 
as  the  whole  of  the  work  underground. 
In  some  mines  the  men  are  raised  in 
the  cages  or  skips  used  for  raising  ore, 
and  this  practice  is  increasing  with 
the  increasing  use  of  wire-rope.  Fig.  43. 

91.  Safety  Catch. — Sometimes  the  cages  are  fitted  with 
safety  catches  which  are  intended  to  prevent  the  fall  of  the 
cage  in  case  of  the  ropes  breaking.     One  very  convenient 
form  of  this  contrivance  consists  of  a  strong  spring  which 
serves  as  the  connection  between  the  rope  and  the  cage. 
The  weight  of  the  loaded  cage  keeps  this  spring  bent,  but 
if  the  rope  should  break  it  is  at  once  relaxed,  and,  by  its 
recoil,  sets  free  some  strong  teeth,  which  immediately 
force  themselves  into  the  shaft  railway  or  guides,  and  so 


C8 


PRINCIPLES   OF   METAL   MINING, 


keep  the  cage  from  falling.  But  all  such  contrivances 
are  liable  to  get  out  of  order  unless  constantly  watched; 
and  as  it  is  difficult  to  induce  men  to  prepare  for  a  danger 
which  seems  very  remote,  many  practical  miners  prefer 
to  do  without  all  such  appliances,  and  to  trust  entirely 
to  the  perfection  of  the  rope,  which  is  constantly  under 
the  inspection  of  the  manager  or  his  appointed  agent. 


Fig.  44.  "  Fig.  45. 

92.  From  shallow  depths,  or  while  sinking,  the  men 
are  often  raised  by  means  of  the  rope  used  for  raising  the 
"  deads."  The  writer  has  been  frequently  brought  up 
from  a  depth  of  between  30  and  40  fathoms  standing 


DEAD  WORK  IN  SHAFTS.  69 

with  one  foot  in  the  kibble  and  holding  on  to  the  rope 
with  his  left  hand;  but  such  a  mode  cannot  be  recom- 
mended for  depths  of  more  than  a  few  fathoms,  especially 
if  the  rope  is  at  all  worn. 

93.  The  Man-Engine. — In  some  of  the  larger  Cornish 
mines  the  contrivance  known  as  the  "  man-engine"  is 
used  for  raising  and  lowering  the  men — a  special  shaft 
being  devoted  to  this  purpose,  except  that  a  ladder-way 
is  also  placed  in  the  shaft. 


Fig.  46. 
The  man-engine  consists  of  a  beam  of  wood  called  the 


O  PRINCIPLES   OP   METAL   MINING. 

"rod,"  a  a,  fig.  46,  which  is  made  to  move  up  and  down 
alternately  through  a  space  of  twelve  feet,  by  means  of  an 
engine  devoted  partially  or  entirely  to  that  purpose.  On 
the  rod,  at  b  b,  steps  are  fixed  twelve  feet  apart,  on  which 
the  men  stand  while  it  is  in  motion,  holding  on  by  iron 
handles  provided  for  that  purpose.  When  it  stops  for  an 
instant  before  the  motion  is  reversed  the  steps  are  level 
with  the  "sollars,"  which  are  placed  in  the  sides  of  the  shaft. 
It  is  evident  that  if  the  men  who  stand  on  the  steps  during 
the  upward  motion  of  the  rod  step  on  to  the  sollars  during 
its  downward  motion,  and  step  back  to  the  rod  when  it 
again  rises,  they  will  be  raised  to  the  surface  by  succes- 
sive lifts  of  twelve  feet,  without  any  labour  on  their  part 
except  the  stepping  off  and  on.  As  many  men  may  thus 
be  brought  up  from  their  work  at  one  time  as  there  are 
steps  on  the  rod,  and,  as  the  sollars  are  fixed  on  both  sides 
of  the  shaft,  an  equal  number  of  men  may  be  carried 
down  at  the  same  time,  each  stepping  on  the  rod  as  the 
man  leaving  work  steps  off.  The  weight  of  the  rods,  with 
all  connections,  averages  about  25  cwt.  per  fathom;  or 
for  a  depth  of  200  fathoms  amounts  to  about  250  tons. 
The  great  weight  is  balanced  by  several  of  the  "  balance 
bobs  "  -to  be  described  hereafter. 

The  man-engine  is  so  great  an  advantage  to  all  con- 
cerned— both  workmen  and  employers — that  it  would 
soon  become  generally  used  in  deep  mines  unprovided  with 
lifting  cages  but  for  its  great  expense.  This  is  very  great 
indeed,  since  most  of  the  shafts  in  deep  and  therefore  old 
mines  are  too  narrow  and  irregular  to  allow  of  its  intro- 
duction without  a  good  deal  of  expense  in  cutting  down 
the  irregularities.  Still,  in  4  large  mines,  the  expense  is 
well  repaid  by  the  advantage. 

94.  The  cost  of  supplying  a  man-engine,  with  driving 
engine,  complete,  to  a  depth  of  200  fathoms — exclu- 
sive of  the  cost  of  the  shaft  itself — cannot  be  taken  at 
less  than  £2000  to  £2500.  The  interest  on  the  larger 
sum  at  5  per  cent.,  with  10  per  cent,  added  for  deprecia- 
tion of  plant  and  repairs,  amounts  to  £375  per  annum. 


CONVEYANCE  AND  RAISING  OF  STUFF.  Tl 

The  cost  of  coal  and  attendance  for  driving  the  engine, 
for  oil,  grease,  etc.,  will  amount  to,  say,  ,£250  per  annum 
in  addition. 

The  labour  of  climbing  from  an  average  depth  of  100 
fathoms  cannot  be  taken  at  less  than  1  hour  daily,  or, 
with  3  shifts  of  50  men  at  an  average  of  5d.,  the  amount 
lost  by  climbing  will  be  each  day  62s.  6d.;  or,  for  a  year 
of  240  working  days,  say,  £801,  showing  a  clear  gain  of 
£175.  For  a  depth  of  310  fathoms  the  advantage  is 
many  times  greater,  since  the  exhaustion  of  the  men  from 
the  labour  of  climbing  and  the  time  occupied  will  increase 
in  a  geometrical  ratio.  However,  setting  aside  all  cal- 
culations of  cost,  it  is  only  necessary  to  look  at  the  men 
who  have  just  come  up  by  ladders  from  deep  mines  to  see 
that  some  mode  of  relieving  them  from  such  excessive 
toil  is  most  necessary. 

The  man-engine  originated  in  Germany,  where  it  is 
called  the  "  fahr-kunst."  The  idea  occurred  to  some  of 
the  German  miners,  who  saw  the  reciprocating  action  of 
the  pump  rods,  to  attach  steps  to  it,  and  this  was  actually 
carried  into  practice.  In  Cornwall  the  idea  of  a  man- 
engine  was  first  carried  into  effect  by  Mr.  Loam,  in 
1835,  at  Tresavean  mine  in  Gwennap,  Cornwall,  and  an 
award  of  £500  was  made  to  Mr.  Loam  for  this  great 
boon  to  the  working  miners  by  the  Royal  Cornwall 
Polytechnic  Society. 


CHAPTER  XIII 

ON   THE   CONVEYANCE   AND   BAISING   OF   STUFF. 

95.  The  earliest  mode  of  bringing  the  ore  and  deads 
from  the  "  pitch,"  or  place  of  work,  to  the  surface,  was 
probably  by  carrying  it  in  baskets  of  wicker-work,  and 
this  mode  is  still  in  use  in  many  foreign  mines.  For 
centuries,  however,  the  mode  most  usually  adopted  has 


72  PRINCIPLES  OP  METAL  MINING. 

been  to  place  it  in  wheel-barrows,  and  to  wheel  it  along  the 
levels.  In  many  metal  mines  this  mode  is  still  the  only 
one  in  use,  but  some  form  of  tram-waggon  is  now  very 
generally  introduced. 

96.  The  first  improvement  was  to  lay  planks  along  the 
rough  floor  of  the  level,  upon  which  the  wheel  of  the 

barrow  would  run  more 
easily.  The  wheel-barrow 
used  for  such  purposes  in 
Cornwall  is  shown  in  fig. 
47.  It  has  no  legs;  is 
Fig.  47.  nearly  parallel  lengthwise; 

and  its  sides  are  but  little  inclined.  Its  ordinary  load  is 
about  1  cwt.  to  1 J  cwt.  It  is  usually  made  on  the  mine, 
and  its  cost  varies  from  8s.  6d.  with  a  wooden  wheel, 
to  12s.  6d.  with  an  iron  wheel.  Such  a  wheel-barrow 
is  admirably  adapted  for  use  underground  in  the  old- 
fashioned  narrow  levels,  and  it  is  far  more  convenient 
for  tipping  sideways  than  is  the  ordinary  navvy  barrow, 
with  wide  sloping  sides  and  long  legs. 

97.  Tram -Waggons.  —  The   introduction  of  a  wider 
system  of  levels,  and  their  increased  length,  due  to  the 
smaller  number  of  shafts  in  deep  mines,  has  led  to  the 
gradual  introduction  of  tram-waggons,  running  upon  four 

wheels.      These    are   sometimes 
made  of  wood  strengthened  with 
iron  bands,  but  are  better  of  iron 
throughout.       Fig.   48    shows   a 
waggon    made    of    boiler-plate. 
This,   when  42  inches  long,  30 
inches  wide,  and  18  to  20  inches 
Fig.  48.— TRAM- WAGGON,  deep,  will  hold  about  a   ton  of 
flanged  wheels.    Door  at  iron  ore;  will  weigh  from  3  to 
end,  hinged  at  a,  made  of  4   cwt.  :   and    cost   from   £5    to 
iron  plates,  riveted.  £Q 

Sometimes  the  waggons  are  made  with  plain  wheels  to 
run  between  tram-plates,  of  the  form  shown  in  fig.  49,  at 
a,  but  a  saving  of  iron  is  effected  by  using  flanged  wheels 


CONVEYANCE  AND   RAISING  OF   STUFF.  73 

running  upon  wooden  rails,  3  inches  high  and  2  inches 
wide,  faced  with  thin  bar  iron,  or  upon  iron  rails  nailed 
to  wooden  sleepers.  Three  forms  of  rail  are  shown  in 
fig.  49,  at  b  c  d.  A  convenient  width  between  the  rails  is 
36  inches,  but  the  writer  has  seen  guages  in  use  in  Corn- 
wall and  South  Wales  varying  from  42  inches  downwards 
to  14  inches,  the  latter  being  used  for  the  narrow  levels 
in  an  old  iron  mine.  The  rails  used  weigh  from  10  Ibs. 
to  20  Ibs.  per  yard  of  length. 


Fig.  40. 

98.  The  tram-waggons  are  pushed  along  by  boys  or 
men,  sometimes  pulled  by  donkeys  or  horses,  and  in  a 
few  instances  hauled  along  by  wire-ropes  or  chains,  which 
are   coiled  around  winding  -  drums  worked  by  station- 
ary engines.      Where  possible  the  rails  should  have  a 
downward  inclination  of  about  half  an  inch  per  fathom  in 
the   direction   of  the    load,   as    this    greatly  facilitates 
the  movement  of  the  heavy  weight,  without  materially 
impeding  the  return  of  the  empty   waggons.      In   the 
iron  mines  of  the  North  of  England  and  South  Wales 
much   greater  inclinations  are   rendered   neccessary   by 
the  situation  of  the  ores,    and   "tail-rope   haulage"  is 
exceedingly  common. 

99.  Methods  Of  Raising  Ore. — The  stuff  having  reached 
the  shaft  has  next  to  be  raised  to  the  surface.     From 
depths  not  exceeding  15  or  20  fathoms,  the  "tackle"  or 
windlass  shown  in  fig.  53  may  be  used  with  advantage. 
This  plan  is  not  to  be  recommended  for  greater  depths, 
as  the  cost  may  be  considerably  lessened  by  the  use  of 
other  appliances — the  "horse-whim,"  derrick  or  whipsey- 
clerry,  water  balance,  or  steam  engine — described  in  the 
chapters  on  machinery  for  raising  ore  and  pumping. 

The  ore  is  raised  either  in  "kibbles,"  "skips,"  or  "cages." 


74 


OF   METAL   MINING^. 


The  kibble  is  simply  an  iron  bucket  made  of  boiler  plates, 
riveted  together  as  shown  in  figs.  41  and  53.  They  are 
attached  to  chains,  hempen  or  wire  ropes,  and  vary  in 
capacity  from  1  to  25  cwt. 

The  small  kibbles  used  with  the  tackle  are  called 
"winze-kibbles."  They  are  made  about  14  inches  high 
and  12  inches  in  diameter;  holding  from  1  cwt.  to  1|-  cwt. 
Whim-kibbles  are  of  nearly  the  same  form  as  winze- 
kibbles,  but  they  are  from  20  to  24  inches  high,  14  to  18 
inches  wide,  and  made  of  somewhat  thicker  plate,  with  a 
loop  below  for  greater  facility  of  upsetting  in  landing. 
They  hold  from  4  to  6  cwt. 

Kibbles  of  very  large  dimensions  are  occasionally  used 

for  deep  shafts,  and 
worked  by  water  wheels 
or  steam  engines.  At 
Dolcoath  mine,  in  Corn- 
wall, very  large  kibbles, 
capable  of  containing  a 
ton  or  more  of  tin  stuff, 
are  worked  in  some  of 
the  old  irregular  shafts. 
The  largest  of  these  are 
more  than  4  feet  high, 
and  about  3  feet  6  inches 
wide. 

When  kibbles  are  used 
in  deep  shafts  it  is  because 
they  are  much  inclined 
and  somewhat  irregular. 
The  lower  side  or  foot- 


Fig.  50.-A,  THE  SKIP,  withahinged 
door  at  a,  wheels  at  b,  and  guide  entir,e  17  l 
pieces  at  c,  c;  d,  d,  cross  timbers  plank"  to  reduce  the  fric- 
let  into  sides  of  shaft;  e,  e,  guides;  tion.  The  amount  of  wear, 
/,  foot-wall;  g,  hanging  wall  of  however,  of  bed-plank 
lode.  ,  ,  .,  ,',  . 

and  kibble  is  very  great, 

the  friction  is  enormous,  and  the  breakages,  owing  to  the 


CONVEYANCE  AND   RAISING  OF  STUFF. 


excessive  strain  on  the  ropes  and  machinery/ are  very 
frequent;  so  that  the  use  of  kibbles  for  deep  or  permanent 
shafts  is  not  to  be  recommended.  A  much  better  plan  is 
to  straighten  the  shaft  as  much  as  possible,  to  put  in 
guides  or  shaft  railways,  and  to  use  skips  running  upon 
wheels  as  shown  in  fig.  50.  These  skips  are  now  com- 
monly raised  by  means  of  wire- rope,  but  unless  the 
railway  be  put  in  very  carefully  the  friction  is  still 
considerable,  and  in  Cornwall  a  speed  of  360  feet  per 
minute  has  rarely  been  exceeded.  For  highly  inclined 
shafts,  the  skips  should  have  wheels  as  shown  in  the 
figure;  but  when  the  shaft  is  nearly  vertical,  simple  guides 
will  suffice.  Fig.  51  is  a  plan  of  a  shaft  with  double 
skip-road  adapted  for  wheels,  and  fig.  52  a  similar  shaft 
arranged  with  "  cover  and  filler"  roads  for  guided  skips. 
The  cost  of  putting  in  a  double  skip-road  or  shaft  rail- 
way will  _vary  from  £1  10s.  to  £3  10s.  per  fathom  of 
length. 


Fig.  52.  —  PLAN  or  DOUBLE 
"COVER  AND  FILLER"  SKIP 
PV.OAD.  A,  the  skip;  i,  the 
"cover  ;"  h,  the  "filler." 


Fig.  51.  —  PLAN  OF  DOUBLE  SKIP- 
ROAD  OR  SHAFT  RAILWAY.  A, 
the  skip;  b,  the  wheels;  c,  c, 
guides;  d,  d,  shaft  timbers; 
e,  e,  the  rails. 

The  skip  shown  in  fig.  50  is  filled  sometimes  at  the 
upper  end,  but  sometimes  the  rails  are  bent  round  so  as 
to  allow  it  to  take  a  horizontal  position  at  the  bottom 
of  the  shaft,  when  it  is  filled  by  opening  the  hinged  door. 
This  door  is  then  secured  with  a  catch  until  it  reaches  the 
surface,  where  the  "  lander"  brings  it  over  his  waggon 
and  opens  the  door,  so  allowing  the  stuff  to  slide  down 
the  sloping  bottom. 


76  TKINCIPLES   OF  METAL  MINING. 

Wherever  possible,  the  use  of  a  pair  of  cages  running 
in  a  vertical  shaft  is  to  be  recommended.  These  are 
arranged  so  that  the  loaded  waggon  from  the  "  end," 
"  stope,"  or  "  face  of  work"  may  be  run  directly  into 
the  cage,  and  raised  to  the  surface  with  only  one  loading. 
In  this  manner  a  much  greater  speed  may  be  attained ; 
and  nearly  twice  the  quantity  may  be  raised  from  the  shaft 
with  the  same  power  as  in  the  case  of  a  pair  of  skips. 

100.  Comparative  Cost. — From  shafts  from.  10  to  15 
fathoms  deep,  two  men  will  raise  on  an  average,  with 
the  tackle,  about  12  tons  in  eight  hours.  The  cost  of  this 
in  Cornwall  is  6s.,  or  say  6d,  per  ton,  or  Jd.  per  "  ton- 
fathom."  For  depths  of  more  than  15  fathoms  a  less 
quantity  will  be  raised,  or  else  a  third  man  will  be 
required,  and  the  cost  will  be  about  |d.  per  ton-fathom. 
A  hempen  rope  about  1-J"  diameter,  called  a  tackle-rope, 
is  generally  used  with  the  tackle. 

With  a  one-horse  whim,  one  man  to  receive  the  stuff 
and  a  boy  to  drive  the  horse,  from  15  to  20  tons  per 
eight  hours  may  be  raised. from  a  depth  of  40  fathoms. 
The  cost  will  be  in  Cornwall  about  9s.,  or,  say,  6d.  per 
ton  as  before,  but  the  depth  being  greater  it  will  only 
be  about  l-6th  of  a  penny  per  ton-fathom.  To  raise  a 
greater  quantity,  or  from  a  greater  depth,  two  horses  will 
be  necessary. 

With  the  "  derrick"  or  "  whipsey-derry"  the  cost  will 
be  a  little  more  than  with  the  horse -whim.  Whim 
kibbles  are  often  raised  by  means  of  chains,  but  the  use 
of  chains  in  shafts  is  not  to  be  recommended. 

With  large  kibbles  working  in  shafts  of  from  150  to 
300  fathoms  deep,  from  20  to  30  tons  per  day  of  eight 
hours  may  be  raised — the  larger  quantity,  of  course,  from 
the  shallower  shaft.  When  engine  power  is  used,  the 
cost  will  be  about  10s.  to  12s.,  or,  say,  l-30th  of  a  penny 
per  ton-fathom  on  an  average.  A  water-wheel  will  save 
about  2-5ths  of  this. 

With  a  well -arranged  skip  and  shaft  railway  the 
cost  of  raising  ore,  even  where  a  steam  engine  is  used, 


CONVEYANCE   AND   RAISING   OF   STUFF.  77 

will  be  reduced  to  about  l-50th  of  a  penny  per  ton-fathom, 
or  less  j  and  with  a  pair  of  cages  in  a  vertical  shaft  with 
good  arrangements  will  not  exceed  1-1 00th  of  a  penny 
per  ton-fathom. 

101.  In  metal  mines,    where    ores  of  a   considerable 
specific  gravity  have  to  be  dealt  with,  large  cages  are 
seldom  needed.      A  waggon   30"  x  42"  x  20"   will   hold 
about  one  ton  of  iron  ore,  and  this  is  as  much  as  it 
will  be  generally  necessary  or  desirable  to  raise  at  one 
time.     With  good  arrangements,  a  shaft  of  12  feet  by 
9  feet  will  be  found  large  enough  to  allow  of  ample 
pumping  space,  a  good  ladder-way,  and  a  pair  of  cages 
capable  of  raising  20  tons  per  hour  from  a  depth  of  200 
fathoms. 

From  the  foregoing  remarks  it  is  evident  that  kibbles 
are  only  suitable  for  shafts  of  moderate  depth,  and  pre- 
ferably for  those  which  are  nearly  vertical.  Cages  are 
only  suitable  for  vertical  shafts,  but  are  valuable  for 
all  depths.  For  inclined  shafts,  skips  running  upon 
wheels  are  most  suitable;  and  it  will  be  worth  while  in 
every  case  to  pay  great  attention  to  the  rails  or  guides 
upon  which  they  run.  Where  the  inclination  of  the  shaft 
from  the  horizontal  does  not  exceed  1  in  3,  as  in  many 
ore  beds  and  some  few  "  flat"  lodes,  the  ore  may  be 
brought  up  in  the  tram-waggons  from  the  levels  without 
using  skips  or  cages,  the  same  tramway  being  continued  up 
the  incline  to  the  surface.  In  all  cases,  if  at  all  possible, 
double  roads  should  be  used,  or  two  pits  should  be  put 
into  communication  to  cause  the  weight  of  the  descend- 
ing cage  to  balance  that  which  is  ascending,  so  that  the 
mineral  only  shall  be  lifted.  Sometimes  where  both 
these  modes  are  for  some  reason  unsuitable,  a  "  dummy" 
counterpoise  may  be  used. 

102.  Ropes. — For  shallow  pits  chain  or  hemp  rope  may 
be  used  with  great  propriety,  because  of  the  facility  with 
which  it  may  be  coiled  round  small  barrels  or  drums ; 
but  for  considerable  depths,  and  especially  where  great 
weights  have  to  be  lifted,  the  use  of  wire  rope  in  some 


78  PRINCIPLES   OP   METAL   MINING. 

form  is  both  safer  and  much  more  economical — and  is, 
indeed,  now  almost  universally  used.  Wire-ropes  may 
be  either  round  or  flat,  of  iron- wire  or  steel.  For  round 
iron-wire  ropes,  drums  of  less  than  12  feet  should  never 
be  used;  for  flat  ropes  and  ropes  of  steel  wire,  drums 
somewhat  smaller  may  be  used,  but  are  not  to  be  recom- 
mended in  general. 

103.  The  following  tables  of  the  equivalent  working 
strengths  of  chain,  hemp  rope,  iron-wire  rope,  and  steel- 
wire  rope,  will  be  useful  to  the  young  student.     They  all 
refer  to  material  of  best  quality.* 

TABLE  1. — WEIGHT  AND  STRENGTH  OF  CHAINS. 

Diameter  of  iron,  r^in.,          H  in.,  H  in. 

Weight  per  Fathom,          5J  Ibs.,      28  Ibs.  49  Ibs. 

Working  Load,  24  cwt.,       54  cwt.,       120  cwt. 

TABLE  2. — WEIGHT  AND  STEENGTH  OF  GOOD  HEMP  ROPE. 

Circumference,  5|  in.,          8  in.,  12  in. 

Weight  per  Fathom,          7  Ibs.,         16  Ibs.,          36  Ibs. 
Working  Load  while  j     M  ^    54  ^  ,      m^ 

Breaking  Strain,  8  tons,  '    18  tons,         40  tons 

TABLE  3. — WEIGHT  AND  STRENGTH  OF  IRON-WIRE  ROPE. 

Circumference,  2J  in.,  Sf  in.,  4|  in. 

Weight  per  Fathom,  4  Ibs.,  9  Ibs.,  20  Ibs. 

Working  Load,  24  cwt.,  54  cwt.,  120  cwt. 

Breaking  Strain,  8  tons,  18  tons,  40  tons. 

TABLE  4. — WEIGHT  AND  STRENGTH  OF  STEEL- WIRE  ROPE. 

Circumference,  If  in.,  2J  in.,  3|  in. 

Weight  per  Fathom,  2£  Ibs.,  '  5£  Ibs.,  12  Ibs. 

Working  Load, ;  24  cwt.,  54  cwt.,  120  cwt. 

Breaking  Strain,  8  tons,  18  tons,  40  tons. 

104.  As  shewn  in  the  tables,  a  very  large  allowance  of 
strength  is  made  for  safe  working,  the  working  load  being 

*Very  complete  tables  of  equivalent  strengths  are  given  in 
Molesworth's  "  Pocket-book  of  Engineering  Formulae." 


MACHINERY   FOR   RAISING   STUFF.  79 

taken  at  less  than  one-sixth  of  the  ultimate  strength. 
With  hemp  rope  and  chains  a  greater  allowance  should 
be  made,  on  account  of  the  imperfection  of  material  and 
workmanship  to  which  they  are  specially  liable.  A  large 
allowance  must  be  made,  too,  for  the  strain  due  to  the 
extra  pull  in  starting.  Sometimes  this  is  somewhat 
relieved  by  mounting  the  bearings  of  the  winding  pulley 
or  drum  upon  springs,  but  even  when  this  is  done  the 
extra  strain  will  be  very  considerable. 

The  weight  of  the  chain  or  rope  itself  must  be  taken 
into  account  when  any  considerable  length  is  used,  and 
this  too  will  be  much  greater  with  chain  or  hemp  rope 
than  with  wire  rope.  Indeed,  for  deep  pits  the  use  of 
chain  would  be  forbidden  by  this  consideration  alone,  as 
a  chain  of  300  fathoms  long,  capable  of  working  with  a 
load  of  24  cwt.,  would  itself  weigh  nearly  one  ton,  while 
a  steel-wire  rope  of  the  same  strength  would  weigh  only 
750  Ibs. 

To  relieve  the  winding  engine,  and  to  enable  it  to  over- 
come the  weight  of  a  long  length  of  rope,  the  size  of  the 
drum  is  made  to  vary,  or  the  speed  of  winding  at  first  is 
reduced.  This  may  be  effected  either  by  using  a  conical 
winding  drum,  or  by  using  a  flat  rope  and  causing  it  to 
wind  upon  itself. 


CHAPTER  XIV. 

MACHINERY   FOR  RAISING   STUFF. 

105.  The  Tackle.— The  first  machine  used  in  mining 
operations  for  raising  ore  or  deads  is  usually  the  tackle  or 
windlass,  shown  in  fig.  53.  This  is  so  simple  that  it 
scarcely  needs  a  detailed  explanation,  but  as  it  is 
usually  made  on  the  spot  by  the  mine  carpenter,  a  few 
words  may  not  be  out  of  place. 

The  carpenter  selects  two  pieces  of  "half-timber"  a  a 
long  enough  to  reach  across  the  shaft,  and  strong  enough 


PRINCIPLES   OP   METAL   MINING. 


to  bear  the  weight.     These  are  called  the  "bearers,"  and 
they  are  afterwards  planked  over,  except  the  small  space 

required  for  the  kibbles. 
In  the  middle  of  these 
half- timber  bearers  the 
uprights  b  b,  made  of 
planks  from  10  to  12 
inches  wide,  4  feet  G 
inches  long,  and  1-J  to 
1|  inches  thick,  are 
morticed.  In  the  upper 
end  of  each  upright  a 
slot,  about  10  inches 
long  and  1 J  inches  wide, 
is  cut,  and  the  bottom 
lined  with  iron,  to  re- 
ceive the  iron  handles, 


Fig.  53. 


and  to  prevent  the  wood  from  splitting.  The  barrel  c 
is  made  of  a  piece  of  Norway  pine,  from  4  to  6  feet  long, 
and  8  or  10  inches  thick.  The  ends  of  the  barrel  are 
strengthened  with  iron  bands  to  prevent  them  from 
splitting  when  the  handles  are  driven  in. 


Fig.  54. 

The  handles  d  d  are  made  of  V  or  11"  round  iron,  bent 
as  shown,  and  squared  and  tapered  at  the  ends  for  driv- 
ing into  the  barrel.  The  handles  serve  also  as  an  axle 
for  the  winding  barrel. 

A  piece  of  wood  e  is  then  fastened  across  the  top  of  the 


MACHINERY   FOR   RAISING   STUFF.  81 

tackle,  and  a  groove  is  made  in  it  to  receive  a  sliding 
piece  f,  which,  being  pushed  out  beyond  the  bend  of  the 
handle,  holds  it  when  required,  keeping  the  load  from 
descending.  Sometimes  stays  are  fixed  extending  side- 
ways from  the  uprights,  as  shown  at  g  g.  The  cost  of 
preparing  and  fixing  this  shaft-tackle  should  not  exceed 
25s.  or  30s.  for  timber,  iron-work,  and  labour.  The 
tackle  is  well  adapted  for  raising  material  from  depths  of 
less  than  15  fathoms;  for  greater  depths,  up  to  50  fathoms, 
the  derrick  or  "whipsey-derry,"  fig.  54,  is  sometimes  used, 
but  it  is  slow  in  operation,  and  has  little  to  recommend 
it  except  its  small  first  cost,  which  is  from  £2,  10s.  to 
£3,  10s. 


Fig,  55. 

106.  The  Horse-Whim,  shown  in  fig.  55,  is  a  much 
more  efiicient  machine.  This,  too,  is  made  on  the  mine, 
the  mode  of  construction  being  as  follows : — The  axle  a  is 
of  oak,  about  12"  diameter,  and  12  or  14  feet  long.  Three 
sets  of  arms  are  morticed  into  this  at  distances  of  6,  8,  and 
10  feet  from  the  lower  end.  Upon  these  arms  wooden 
segments  are  nailed,  and  upon  these  again  the  4-inch 
planks  which  form  the  barrel  or  cage.  Each  end  of  the 
axle  is  bound  with  iron,  and  each  has  an  iron  centre 
attached.  The  lower  one  works  in  a  block  of  stone, 
shown  at  &,  the  upper  in  an  iron  socket  fixed  to  the  span 
beam  c  c.  This  is  made  of  a  piece  of  Norway  or  Swedish 
fir,  36  feet  long  and  about  10  inches  square,  supported 
by  the  legs  d  d,  which  are  morticed  into  the  beam,  and 
frequently  strengthened  with  iron  strapping  plates.  Stays 
are  added  at  e  e.  The  barrel  f  is  10  feet  diameter:  be- 
18u  j- 


82  PRINCIPLES   OP   METAL   MINING. 

neath  it  is  placed  the  driving  beam  gg,  30  feet  long,  and 
strengthened  by  the  stays  h  li.  At  one  or  both  ends  of 
the  driving  beam  a  bar  of  iron  is  fixed  with  a  yoke  to 
which  a  horse  may  be  attached.  The  total  cost  of  such  a 
whim  as  here  described  is  under  £20,  and  it  is  a  very 
efficient  machine  indeed. 

107.  The  Poppet  Heads  are  shown  over  the  shaft  to 
the  right  of  the  whim.    The  construction  is  as  follows : — 
Two  timber  "  horses  "  i  i  are  first  formed.     The  legs  are 
12  feet  long,  and  as  thick  as  possible,  but  not  less  than 
10  or  12  inches.     These  are  partly  sunk  in  the  ground, 
and  the  upper  ends  are  morticed  into  the  "  caps,"  which 
are  9  or  10  feet  long.    The  horses  are  placed  one  on  each 
side  of  the  shaft,  about  5  or  6  feet  apart,  the  centre  of 
the  space  between  being  in  line  with  the  span-beam  of 
the  whim. 

Carriers  are  placed  across  the  horses,  and  the  bearings 
of  the  pulleys  rest  upon  these.  The  pulleys  are  usually 
of  different  sizes.  Where  chain  or  hemp  ropes  are  used 
for  hauling,  one  may  be  about  4  feet  and  the  other  2  feet, 
each  being  4  inches  wide.  Wire  rope  is  seldom  used 
with  a  whim,  but  should  it  be  used,  the  pulleys  must 
be  much  larger.  The  total  cost  of  the  poppet  heads  for 
whim  drawing  will  not  much  exceed  £6.  Very  similar 
poppet  heads,  but  larger,  are  used  in  many  cases  when 
winding  with  a  steam  engine  or  water  wheel. 

108.  It  is  not  often  that  water  wheels  are  arranged  for 
hauling  purposes,  although  in  some  instances,  as  at.  Wheal 
Friendship,  near  Tavistock,  they  have  been  used  with 
excellent  effect.     The  only  peculiarity  is  the  application 
of  suitable  gear  for  reversing  or  stopping  the  motion. 
There  is  no  great  difficulty  in  this,  but  the  inconvenience 
is  sufficient  to  prevent  their  extended  use  for  such  a  pur- 
pose in  shallow  mines,  and  in  deep  mines  a  sufficiency  of 
water  power  is  rarely  available,  and  what  there  is  may 
be  often  more  advantageously  used  for  pumping.     We 
shall  therefore  reserve  our  remarks  upon  water  wheels, 
for  the  chapter  on  "  Pumping  Machinery." 


MACHINERY   FOR    RAISING   STUFF. 


83 


An  easy  and  convenient  but  not  economical  mode  of 
using  a  fall  of  water  for  winding  purposes  is  shown  in 
section  in  fig.  56.  The  water  enters  at  a,  and  falls  upon 
the  leaves  or  buckets  of  the  wheel  b,  making  its  escape  at  c. 


Fig.  56. 

A  cogwheel  is  mounted  upon  the  axisyoutside  the  working 
barrel,  which  serves  to  communicate  motion  to  the  wind- 
ing drum  g,  shown  in  fig.  57.  The  motion  is  stopped  or 


Fig.  57. 

reversed  by  the  handle  d,  which  moves  the  valve  e,  bring- 
ing the  channel  successively  into  the  positions  shown  at 
A  and  B.  The  whole  arrangement  is  as  shown  in  fig.  57, 


84  PKINCIPLES   OF   METAL   MINING. 

where  a  is  the  inlet  for  the  water,  h  is  the  case  containing 
the  working  wheel,  i  is  the  cogwheel  fixed  on  its  axis, 
and  g  the  winding  drum.  This  mode  of  using  water  power 
Is  suggested  by  a  working  model  which  is  now  in  the 
Museum  of  Practical  Geology  in  Jermyii  Street,  London. 
It  is  cheap,  compact,  and  easily  constructed,  and  but  little 
likely  to  get  out  of  repair,  but  the  author  is  not  aware 
that  it  is  anywhere  in  use.  When  the  fall  of  water  is 
great  this  simple  arrangement  will  be  found  very  efficient. 
109.  The  Water-Balance. — In  many  of  the  open  works 
on  the  northern  side  of  the  great  coal  basin  of  South  Wales, 
water -balance  machines  are  largely  used  for  winding 
purposes,  and  for  mines  of  not  more  than  100  fathoms 
deep;  in  a  district  affording  a  good  supply  of  water,  and 
free  drainage  by  means  of  adits,  they  may  be  highly  recom- 
mended. Sometimes  they  are.  used  when  there  is  no 
drainage,  the  water  being  pumped  up  from  the  bottom  by 
an  engine,  but  this  is  not  to  be  recommended.  In  some 
cases  the  machines  are  placed  at  different  levels,  so  that  the 
same  water  is  used  five  or  six  times  over  as  many  succes- 
sive lifts.  The  tram,  containing  from  12  to  20  cwt.,  is 
placed  in  a  cage  over  an  empty  water  bucket,  and  the 
empty  tram  on  a  similar  bucket  at  the  top.  Water  is 
then  made  to  flow  into  the  upper  bucket  until  its  weight 
is  great  enough  to  cause  it  to  descend,  so  raising  the  filled 
tram.  On  the  arrival  of  the  full  bucket  at  the  bottom  of 
its  fall  a  self-acting  valve  opens  and  the  water  is  dis- 
charged, so  allowing  the  process  to  be  repeated.  The 
buckets  are  made  of  J"  boiler-plate,  circular  in  form,  and 
some  hold  more  than  2  tons  of  water.  The  landing  chain 
is  balanced  by  a  chain  which  hangs  below  each  bucket, 
and  guide  chains  are  used  to  keep  the  buckets  from  strik- 
ing each  other  when  the  shafts  are  not  divided.  A  speed 
of  300  to  400  feet  per  minute  is  easily  attained  by  this 
machine,  and  the  total  cost  of  raising  stuff  is  about  IJd. 
per  ton  per  50  fathoms.  For  great  depths  the  weight  of 
the  machinery  becomes  so  great  that  the  economy  is 
reduced  or  disappears.  Somewhat  similar  machines  are 


MACHINERY    FOR   RAISING   STUFF.  85 

used  in  some  of  the  iron  mines  of  North  Lancashire  and 
Cumberland. 

110.  The  Steam  Engine. — For  hauling  in  deep  mines 
a  steam  engine  is  generally  necessary,  and  although  many 
forms  of  steam  engine  are  employed  for  this  purpose,  our 
remarks  will  apply  to  two  only — the  double-acting  high- 
pressure   condensing  engine,   and  the  double-cylindered 
horizontal  engine.     Both  these  machines  work  the  steam 
expansively,  and  both  give  good  duty  when  in  good  order 
and  when  well  attended;  but  the  preference  in  the  future 
will  probably  be  given  to  the  horizontal  engine,  every- 
where, at  any  rate,  except  in  Cornwall. 

The  Cornish  winding  engine  differs  but  little  from  the 
Cornish  pumping  engine,  hereafter  to  be  described,  except 
that  it  is  double  acting,  i.e.,  it  takes  its  steam  on  both 
sides  of  the  piston  instead  of  only  on  the  upper  side.  It 
is,  however,  supplied  with  a  heavy  fly  wheel  to  equalise  the 
motion  as  much  as  possible.  The  driving  crank  is  placed 
between  the  fly  wheel  and  the  winding  drum.  Neither 
a  very  rapid  nor  an  equal  motion  is  obtained  by  this 
form  of  engine,  and  the  double-cylindered  horizontal 
engine  is  on  the  whole  much  to  be  preferred.  The  Cornish 
double-acting  engine  is  sometimes  used  for  pumping,  or 
for  driving  stamping  or  crushing  machinery. 

111.  Horizontal  Engine. — The  cylinder  of  this  engine 
is  fixed  in  a  horizontal  position,  as  shown  at  AB  in  fig. 
58.    High-pressure  steam  is  admitted  alternately  on  each 
side  of  the  piston.     The  piston-rod  is  terminated  by  the 
crosshead  g,  which  works  backwards  and  forwards  be- 
tween the  guides  a  b.     To  this  crosshead  the  connecting 
rod  g  c  is  attached,  and  this  turns  the  drum  or  fly-wheel 
by  means  of  the  crank  C  and  the  main  shaft  r.     The 
whole   is   fixed   on    heavy   masonry   as    at   C  D.       To 
equalise  the  motion  two  cylinders  are  used  with  their 
cranks  at  right  angles,  so  that  one  is  exerting  its  greatest 
amount  of  force  while  the  other  is  at  its  dead  point.     A 
common  form  of  governor  is  shown  at  G.     To  economise 
steam  it  is  used  expansively.     The  condenser  and  its 


86 


PRINCIPLES   OF   METAL   MINING. 


connections  are  nob  shown  in  the  sketch,  but  they  may  be 
placed  in  any  convenient  situation.  For  winding  purposes 
they  are  fittad  with  reversing  gear  and  powerful  friction 
brakes. 


SP 


Fig.  58. 

The  advantage  of  the  horizontal  over  the  beam  winding 
engine  is  greater  compactness  and  less  first  cost  for  equal 
power,  a  saving  of  cost  in  the  necessary  buildings,  and,  if 
two  cylinders  be  used,  a  more  equable  motion.  Its  only 
disadvantage  is  that  the  cylinders  are  apt  to  lose  their  true 
form,  the  lower  part  becoming  more  worn  than  the  upper, 
owing  to  the  weight  of  the  piston.  A  remedy  for  this 
has  been  found  by  mounting  the  piston  on  the  centre  of  a 
long  piston-rod  which  passes  through  stuffing  boxes  placed 
at  each  end  of  the  cylinder. 

Every  winding  engine  should  be  fitted  with  some  form 
of  indicator,  showing  the  attendant  the  exact  position  of 
the  skip  or  cage  in  the  shaft  at  a  glance,  as  in  this  way 
many  accidents  from  over-winding  may  be  prevented.  To 
prevent  loss  of  steam  by  condensation  in  the  steam-pipe, 
cylinders,  etc.,  these  parts,  as  well  at  the  top  of  the  boilers 
themselves,  are  covered  with  some  non-conducting  mate- 
rial. The  modes  of  doing  this  will  be  explained  in  a 
future  chapter.  The  principal  forms  of  boilers  will  also 
be  there  described  and  illustrated* 


DRAINAGE  OF  MINES.  87 

CHAPTER  XV. 

THE  DRAINAGE  OP  MINES. 

112.  THERE  are  few  situations  where  workings  can  be 
carried  to  any  considerable  depth,  below  the  surface  of  the 
ground  without  interruption  from  the  accumulation  of 
water.     The  surrounding  rocks  always  contain  more  or 
less  of  water,  which   occupies  their  joints,  fissures,  or 
cavities,  and  this  water  rapidly  accumulates  wherever  the 
excavations  are  deepest,  and  must  be  removed  in  order 
that  the  works  may  be  carried  on. 

113.  Adit  Levels  are  driven  in  many  cases  to  draw  off 
this  water  as  fast  as  it  gathers,  wherever  the  formation  of 
the  ground  is  favourable.     Such  adit  levels  are  shown  in 
fig.  2,  p.  25,  and  fig.  11,  p.  35.     In  some  instances  very 
extensive  districts  have  been  drained  by  adits  to  depths 
of  many  fathoms.   Thus  the  great  Gwennap  adit  in  Corn- 
wall, which  was  constructed  about  a  century  ago,  drains 
nearly  30  square  miles  of  country  by  means  of  branches 
to  a  depth  varying  from  30  to  90  fathoms.     The  total 
length  of  this  adit,  with  its  branches,  is  about  40  miles. 
Another  great  adit,  known  as  the  Ernst  August  adit,  was 
finished  a  few  years  ago  in  Saxony,  and  drains  a  large 
series  of  mines  in  the  Hartz  Mountains,  some  of  them  to 
a  depth  of  214  fathoms.     This  adit,  with  its  branches,  is 
14  miles  in  length;  part  of  it  is  navigable  by  boats; 
and  it  occupied  nearly  13  years  in  construction — costing 
£85,500. 

Sometimes,  however,  an  adit  is  inadmissible  or  insuffi- 
cient, thus — if  the  mine  is  situated  in  a  very  low  place,  if 
it  occupies  an  isolated  portion  of  country,  if  the  water  be 
required  at  the  surface  for  ore-dressing  operations,  or  if 
the  ground  be  so  little  uneven  that  a  very  long  level 
would  be  required  in  order  to  drain  any  considerable 
depth  of  workings,  some  different  mode  of  drainage  is 
necessary. 


88 


OP  METAL 


114.  Pumps  and  Pitwork. — In  trial  shafts  for  work- 
ings of  small  extent,  or  in  a  country  already  partially 
drained  by  surrounding  mines,  water  buckets  may  be 
used,  the  water  being  raised  by  means  of  the  tackle 
shown  in  fig.  53,  or  the  horse-whim,  fig.  55.  As  the 
water  increases,  however,  this  mode  is  found  quite  inade- 
quate, and  some  form  of  pump  is  necessary. 

The  common  suction  pump,  shown  in  fig.  59,  is  rarely 
•used  in  mining  operations,  as  it  will  only  raise  water  to  a 
height  of  about  30  feet,  but  occasionally,  and  for  tempo- 
rary purposes,  such  pumps  are  used  in  successive  lifts. 
The  mode  of  action  is  as  follows : — 

The  long  pipe  A  B  is 
called  the  suction  pipe,  and 
it  must  be  long  enough  to 
reach  into  the  water  in  the 
well.  The  upper  end  of  the 
suction  pipe  is  furnished 
with  a  valve  E  opening  up- 
wards. Above  the  suction 
pipe  is  the  working  barrel 
C,  containing  a  well-fitting 
piston  p,  which  is  worked 
up  and  down  by  the  lever 
or  brake-staff  D.  This  piston 
or  "bucket"  contains  a  valve 
v  opening  upwards.  When 
the  working  begins  the  water 
in  the  suction  pipe  A  B 
stands  at  the  same  level  as 
that  in  the  well.  On  raising 
the  piston  as  indicated  by 


Fig.  59. 


the  arrow,  the  valve  v  rises, 


and  the  air  between  it  and  the  water  in  the  suction 
pipe  is  rarefied,  and  the  pressure  of  air  on  the  water  in 
the  well  causes  it  to  rise  in  the  pipe.  When  the  piston  is 
depressed  as  at  E  the  valve  v  at  the  top  of  the  suction  pipe 
closes,  that  in  the  piston  v  opens,  and  the  excess  of  air 


DRAINAGE   OF  MINES.  89 

between  v  and  v  passes  out  into  the  general  atmosphere. 
The  piston  is  now  again  drawn  up,  the  water  rises  again 
in  the  suction  pipe,  and  at  length — if  the  suction  pipe  is 
not  more  than  30  fee-t  long — passes  through  the  valve  v 
into  the  working  barrel.  The  piston  now  again  descends, 
and  the  water  passes  through  its  valve  v',  and  when  it 
is  again  drawn  up  this  valve  closes,  the  piston  serves  as 
a  bucket  to  raise  the  water  as  far  as  the  spout,  from 
which  it  flows  in  an  intermittent  stream.  The  water 
thus  rises  because  the  pressure  of  the  air  upon  its  surface 
in  the  well  is  greater  than  the  pressure  in  the  suction 
pipe.  If  all  the  air  in  the  pipe  were  to  be  withdrawn  it 
would  rise  until  the  weight  or  pressure  of  water  AB  was 
the  same  as  that  of  the  air  on  the  water  in  the  well,  or 
about  15  Ibs.  to  the  square  inch,  varying  a  little  from 
time  to  time.  This  pressure  is  given  by  a  column  of 
water  about  34  feet  high.  Owing  to  the  difficulty  of 
making  all  the  fittings  air-tight,  about  30  feet  is  all  that 
can  be  ordinarily  reckoned  upon. 

Practically,  it  is  found  that  if  the  distance  AB  is  30  feet 
or  under,  water  may  be  raised  by  means  of  this  pump,  but 
if  more  than  30  feet,  the  pump  will  fail.  For  greater 
depths,  therefore,  the  pump  is  modified  slightly,  as  shown 
in  fig.  60.  The  suction  pipe  a,  now  called  the  "  wind- 
bore"  or  "  snore,"  is  reduced  to  about  10  or  12  feet,  and 
pieces  of  pipe,  called  "  pumps,"  are  added  above  the 
working  barrel  to  the  required  or  most  convenient  height 
— often  more  than  100  ft.  The  whole  arrangement  is 
now  as  shown  in  fig.  60,  and  is  called  a  "bucket"  or 
"drawing"  lift :  a  is  the  windbore,  b  is  the  "door-piece" 
containing  the  valve  or  "  clack  "  c;  o  is  the  door,  d  is  the 
bucket  with  its  clack,  e  is  the  working  barrel,  which  is 
bored  truly  cylindrical,  f  is  the  first  of  the  "  pumps," 
all  of  which  are  about  1  inch  greater  in  diameter  than 
the  working  barrel.  The  different  pieces  are  made  with 
flanged  joints  as  shown,  for  convenience  of  fixing;  g  is 
the  "  collar-launder,"  from  which  the  stream  of  water  is 
delivered. 


90  PRINCIPLES  OF  METAL  MINING. 

This  kind  of  drawing  lift  is  well  suited  for  use  in  a 
shaft  which  is  being  continually  deepened,  as  additional 
pumps  may  be  added  at  the  top  from  time  to  time.  If, 
however,  the  depth  is  more  than  about  30  fathoms,  the 
water  is  usually  raised  in  two  or  more  distinct  lifts — the 
drawing  lift  delivering  its  water  from  the  collar-launder 
rt  fig.  61,  into  a  cistern  A,  from  which  it  is  forced  to  the 
surface  by  the  "  plunger"  or  ram  a,  shown  in  the  figure. 
By  the  ascent  of  the  plunger  "pole"  a  in  the  "  case"  b,  the 
water  which  fills  the  cistern  A  is  made  to  rise  through  the 
wind-bore  h  and  clack  c  into  the  H  piece  H.  "When  the 
pole  descends,  the  clack  c  closes,  the  water  raises  the  clack 
e,  and  passes  upwards  into  the  pumps  above.  As  the 
pole  again  rises,  the  clack  e  is  closed,  c  opens,  and  a  fresh 
portion  of  water  passes  into  the  H  piece.  The  cistern  is 
kept  full  by  the  delivery  of  water  from  the  top  of  the 
drawing  lift  by  the  collar-launder  r,  and  also,  in  many 
cases,  by  the  water  from  the  upper  portion  of  the  mine, 
which  is  led  into  it  instead  of  being  allowed  to  fall  to 
the  bottom  of  the  mine;  f  is  the  top  pump  of  the  draw- 
ing lift,  and  f  the  bottom  pump  of  the  plunger  lift.  The 
plunger  pole  a  works  in  the  case  b  through  a  stuffing  box 
at  i.  The  mode  of  attaching  the  plunger  pole  a  and  the 
bucket-rod  k  to  the  main  rod  1 1,  by  means  of  the  "glands" 
in  m,  and  the  "  set-offs"  n  n,  is  clear  from  the  figure. 

115.  The  pumps  are  made  of  cast  iron,  generally  in 
lengths  of  9  feet,  but  with  a  few  shorter  "matching  pieces" 
in  3  and  6  feet  lengths.  They  are  cast  about  f  ths  to  f  ths 
of  an  inch  thick,  according  to  size,  intended  height  of  lift, 
etc.,  with  several  projecting  ribs  for  strength.  The  flanges 
are  about  1  in.  thick.  The  valves  or  "  clacks"  are  usually 
of  leather  strengthened  with  iron,  and  it  is  here  that  the 
wear  is  greatest.  The  chief  peculiarity  is,  that  the  hinges 
or  centres  of  the  valves  work  within  guides  instead  of  upon 
centres,  so  that  the  whole  valve  has  liberty  to  rise  a  few 
inches,  thus  giving  a  greater  water  space  in  the  early  part 
of  the  stroke. 

Sometimes  valves  of  metal,  variously  constructed,  are 


bBAINAGE   OP   MINES. 


91 


used,  and  occasionally  the  valves  are  partly  or  entirely 
made  of  india-rubber. 

For  convenience  of  access  to  the  valves  they  are  placed 
in  "  door-pieces,"  as  shown  in  side  view  in  fig.  60,  where 
o  is  a  movable  door  giving  access  to  the  valve  c. 


Fig.  60. 


Fig.  61. 


116.  The  cisterns  for  the  successive  lifts  are  made  of 


02 


PRINCIPLES   OP   METAL   MINING. 


wood  3  inches  or  more  in  thickness,  strongly  bound  with 
iron  strapping  plates,  and  supported  on  strong  "  bearers," 
xx}  fig.  60,  which  are  let  into  the  sides  of  the  shaft. 

117.  Sometimes  the  water  to  be  raised  is  of  a  highly 
corrosive  nature,  especially  that  from  copper  and  lead 
mines.     In  such  cases  it  is  good  economy  to  make  the 
valve  seats,  working  barrel,  and  other  important  parts,  of 
gun-metal,  and  to  line  the  pumps  with  thin  staves  of  oak 
or  other  hard  wood. 

118.  The  "  pumps"  are  fastened  together  with  bolts  and 

nuts,  "  flange-pins,"  as  they  are 
called  in  Cornwall,  where  it  is 
customary  to  place  between  the 
flanges  rings  of  thin  iron  bound 
round  with  "  bal-shag,"  a  coarse 
kind  of  flannel.  This,  when  tightly 
screwed  up,  makes  the  joint  air- 
tight, while  it  does  not  interfere 
with  the  ready  separation  of  the 
pumps  in  case  of  need. 

119.  The  "main  rod,"  part  of 
which  is  shown  at  II,  fig.  61,  is  in 
deep  mines  made  of  the  longest 
and  straightest  balks  of  Norway 
pine  which  can  be  obtained.  The 
secondary  rods  are  attached  to  this 
by  "set-offs,"  as  shown  at  nn  in  the 
same  figure.  The  different  lengths 
of  the  main  rod  are  halved  together, 
bolted  through,  and  secured  with 
strong  strapping  plates. 

The  upper  end  is  attached  to  the 
outer  end  of  the  engine  "  beam"  or 
"  bob "    by    wrought-iron    straps, 
secured  by  bolts  b  and  cottars  c,  as 
shown  in  fig.  62. 
At  intervals  down  the  shaft  catch-pieces  c  c  are  secured, 
and  bearers  fixed  across  dd,  in  order  to  take  up  the 


Fig.  62. 


DRAINAGE    OP   MINES. 


93 


weight  of  the  rods  in  case  of  a  breakage,  to  prevent  the 
whole  mass  of  many  tons  weight  from  falling  to  the 
bottom  of  the  shaft.  They  also  prevent  the  engine  from 
making  too  long  a  stroke,  or  going  too  far  out,  and  so 
breaking  off  the  cylinder  cover. 

The  water  is  raised  in  the  lower  or  drawing  lift  by 
the  up  or  "  iii-door"  stroke  of  the  engine,  but  the  remain- 
ing, or  plunger  lifts,  are  worked  by  the  down  or  out-door 
stroke;  the  weight  of  the  rods  forcing  the  water  up  the 
column  of  pumps. 


01234567831) 


Fig.  63. 

120.  Balance  Bobs. — When  the  mine  is  deep  the  weight 
of  the  rods  is  more  than  sufficient  for  this  purpose,  and 
the  surplus  is  generally  counterbalanced  by  "  balance- 
bobs,"  placed  either  at  surface  or  in  chambers  excavated 
by  the  side  of  the  shaft  underground.  Thus,  at  Davey's 
engine  at  the  consolidated  copper  mines  in  Gwennap, 
Cornwall,  the  main  rod  was  one-third  of  a  mile  long,  and 
weighed  95  tons.  The  other  rods  weighed  40  tons,  or 
together  135  tons,  39  tons  were  required  to  balance  the 


04 


PRINCIPLES   OF   METAL   MINING. 


column  of  water  in  the  pumps,  and  the  remaining  96 
tons  were  balanced — partly  by  counter-weights,  partly 
by  special  hydraulic  machinery.  One  of  these  balance- 
bobs  is  shown  at  fig.  63. 

For  raising  the  heavy  portions  of  "  pit-work,"  as  this 
pumping  machinery  is  called,  a  powerful  "capstan"  is  fixed 
just  outside  the  engine-house. 

Very  few  of  the  shafts  in  the  Cornish  mines  are  vertical, 
and  many  are  of  varying  inclina- 
tion, so  that  it  is  necessary  not 
only  to  provide  friction  rollers,  but 
also  to  connect  the  different  sections 
of  the  main  rods  by  angle-bobs.  One 
mode  of  doing  this  is  shown  in  fig. 
G4,  where  a  portion  of  the  ground 
at  the  side  of  the  shaft  is  cut  away 
for  the  reception  of  the  "balance- 
bob"  v,  the  arms  of  which  are 
pivoted  to  sections  of  the  rod  aaa. 
Other  modes  of  effecting  change  of 
motion  by  friction  wheels  and  guide 
rails  are  used  where,  from  the  hard- 
ness of  the  ground  or  other  reasons, 
Fig.  64  this  mode  is  inadmissible. 


CHAPTER  XYI. 

OF  MACHINERY  FOR  WORKING  PUMPS. 

Many  different  forms  of  machinery  are  used  for 
giving  motion  to  the  pumps  which  drain  mines,  but  the 
more  important  and  permanent  forms  are  generally  com- 
prised under  the  two  heads  of  "  WaterWheels"and  "  Steam 
Engines."  The  water  wheels  used  are  mostly  of  the  kind 
termed  "  overshot,"  and  the  most  efficient  of  the  steam 
engines  used  are  those  known  as  Cornish  pumping  engines, 


MACHINERY  FOR  WORKING  PUMPS.         95 

122.  Water  Wheels.— For  falls  of  water  from  20  up 
to  50  feet,  the  large  proportion  of  useful  effect,  and  the 
simple  construction  of  the  overshot  water  -wheel,  will 
probably  account  for  its  almost  universal  adoption.  To 
apply  an  overshot  water  wheel  for  pumping  purposes, 
little  more  is  necessary  than  the  attachment  of  a  crank 
and  connecting  rod  to  one  end  of  its  axle.  The  other 
end  of  the  connecting  rod,  which  may  be  short  or  long, 
in  one  or  many  pieces,  is  attached  to  the  king  post  of  a 
balance  bob,  and  a  reciprocal  motion  is  at  once  obtained 
through  the  revolution  of  the  crank.  Sometimes  the 
power  is  transmitted  from  the  wheel  to  the  pump  rods 
by  means  of  a  wire  rope  or  chain,  and  the  weight  of  the 
descending  pump  rods  takes  up  the  slack  of  the  rope  and 
keeps  it  tight  on  the  return  journey.  Fig.  65  shows  this 
arrangement,  but  it  is  rarely  adopted  where  the  wheel  is 
so  close  to  the  pumping  shaft  as  is  there  shown. 


Fig.  65. 

In  order  to  get  the  largest  proportion  of  work  out  of 
a  given  fall,  the  wheel  is  frequently  made  several  feet 
higher  than  the  total  fall.  The  water  is  then  brought 
upon  the  shoulder  of  the  wheel  as  shown  in  fig.  66;  the 
launder  a  having  a  little  fall  given  to  it,  so  that  the 
water  may  reach  the  wheel  with  a  little  more  velocity 
than  that  of  the  circumference  of  the  wheel  itself.  The 
wheel  works  more  smoothly  when  ciealt  with  in  this 


96  PEINCIPLES   OP   METAL   MINING. 

manner  than  in  any  other.  The  water  should  reach  the 
wheel  at  the  point  b,  which  is  between  30°  and  40°  from 
the  top  of  the  wheel  c.  The  wheel  shown  in  the  fig.  is  of 
iron,  having  10  wrought-iron  arms  dd  ri vetted  or  bolted 
to  the  centre,  and  to  the  shrouding.  The  shrouding  e  e  e 


Fig.  66. 

is  in  segments,  which  overlap  and  are  bolted  together 
between  the  arms.  The  buckets  are  covered  by  this  shroud- 
ing, but  a  small  portion  is  removed  in  order  to  show 
them  at  b.  The  axle  of  the  wheel  works  upon  brasses 
fitted  into  plummer  blocks,  which  are  mounted  upon  piers 
or  "loadings"  of  masonry.  In  all  water  wheels  the 
water  should  be  brought  on  to  the  wheels  in  a  thin  sheet 
of  somewhat  less  width  than  the  breast  of  the  wheel 
itself;  the  buckets  should  be  large  enough  to  receive  all 
the  water  without  any  overflow  at  the  sides,  and  so 
curved  as  to  hold  it  all  until  nearly  at  the  lowest  point, 
and  then  to  discharge  it  all  at  once  before  that  part  of 
the  wheel  begins  to  rise.  Falls  of  water  may  also  be 
utilised  by  means  of  "  breast  wheels/'  "  Poncelot  wheels," 
"undershot  wheels,"  "turbines,"  and  "water-pressure 
engines,"  but  the  space  at  our  disposal  will  not  allow  of 
their  description  here. 

123.  Pumping  Engines. — It  is  evident  that  any  form 
of  steam  engine  may  be  so  arranged  as  to  give  an  alter- 
nate motion  to  the  pump  rods  in  the  shaft j  but  for 


MACHINERY  FOR  WORKING  PUMPS. 


97 


Tier.  67.— ELEVATION  (part  sectional)  of  a  CORNISH  PUMPINC* 

ENGINE. 
18B  G 


98  PRINCIPLES   OF   METAL  MINING. 

permanent  works,  where  large  quantities  of  water  Lave 
to  be  continuously  raised,  the  Cornish  pumping  engine, 
in  combination  with  the  Cornish  tubular  boiler  and 
arrangement  of  flues,  has  proved  itself  superior  to  all  its 
competitors.  The  Cornish  pumping  engine  may  be  de- 
scribed as  a  single-acting,  high-pressure  condensing  engine. 
These  engines  are  of  course  constructed  at  an  engineers' 
establishment  away  from  the  mine.  They  are  very  simple 
and  strong  in  construction,  and  require  but  little  repair. 
When  once  fairly  at  work,  many  of  them  work  continu- 
ously for  years,  with  only  occasional  stoppages  for  pack- 
ing the  piston  or  other  minor  repairs,  so  that  it  is  not 
necessary  for  the  young  miner  to  have  more  than  a 
general  idea  of  their  construction  and  mode  of  working. 
This  is  given  in  fig.  67.  A  is  the  cylinder,  B  the 
piston,  C  the  piston-rod,  which  is  attached  by  the  links 
III  of  the  "parallel  motion"  to  the  inner  or  "in-door" 
end  D  of  the  great  beam  or  "bob"  D  D'.  To  the 
outer  end  D'  the  upper  end  of  the  main  pump  rod  is 
attached.  The  beam  is  usually  made  unequal,  i.e.,  the 
inner  portion  from  the  gudgeon  E  to  the  end  I)  is 
longer  than  from  the  same  gudgeon  to  the  outer  end 
D'.  The  length  of  stroke  in  the  pumps  is  thus  less  than 
that  in  the  cylinder,  and  the  velocity  of  the  water  less  in 
the  same  proportion  than  that  of  the  piston.  This  is 
done  to  lessen  the  shock  of  the  water  in  the  pumps  on 
the  sudden  closing  of  the  valves  when  the  stroke  is 
reversed.  Engines  with  10'  stroke  in  the  cylinder  have 
often  6',  8',  or  9'  only  of  stroke  in  the  pumps.  F  is  the 
steam  port  communicating  with  the  top  nozzle  G.  This 
top  nozzle  contains  three  valves,  of  which  only  the  centre 
one,  called  the  equilibrium  valve,  is  shown  in  the  draw- 
ing at  H.  This  communicates  through  the  equilibrium 
pipe  I  with  the  lower  port  J.  and  so  with  the  space  in 
the  cylinder  A  under  the  piston  B.  K  is  the  bottom 
nozzle  containing  L,  the  exhaust  valve  which  covers  the 
entrance  to  the  eduction  pipe  M.  This  communicates 
with  the  condenser  N,  and  this  again  by  the  foot  valve 


MACHINERY   FOR  WORKING   PUMPS. 

O  with  the  air  pump  P.  The  condenser  and  air  pump 
stand  side  by  side  in  a  cistern  of  cold  water.  The  mode  of 
starting  and  working  may  be  briefly  described  as  follows. 
1S4.  Starting  the  Engine. — When  it  is  intended  to 
start,  and  the  steam,  is  at  the  required  pressure  in  the 
boiler,  all  the  valves  are  opened  by  the  engineer,  when 
the  steam  speedily  fills  the  cylinder  and  all  the  valves  and 
passages,  and,  rushing  through,  forces  out  the  air.  This  is 
called  blowing  through .  The  cylinder  retains  the  air  longest, 
and  to  get  rid  of  it  after  the  steam  has  blown  through  for 
a  few  minutes,  the  "steam"  valve,  which  is  placed  on  the 
left  hand  side  of  the  equilibrium  valve  H,  shown  in  fig. 
67,  is  closed  for  a  little.  The  steam  in  the  eduction  pipe 
is  soon  condensed  by  the  cold  water  around  the  conden- 
ser, and  the  air  rushes  from  the  cylinder  to  supply  its 
place.  The  steam  valve  is  again  opened  to  blow  this  air 
out  of  the  eduction  pipe,  and  this  alternate  opening  and 
shutting  of  the  steam  valve  may  need  to  be  repeated 
several  times  until  all  the  air  is  out  of  the  cylinder.  The 
engineer  now  examines  his  vacuum  guage  to  see  whether 
he  has  any  vacuum  in  the  condenser.  He  may  probably 
have  a  vacuum  equal  to  two  or  three  inches  of  mercury 
when  he  opens  the  "injection"  cock  (not  shown  in  the 
drawing)  a  very  little,  and  allows  a  little  cold  water  to 
pass  into  the  condenser.  If  this  produces  a  considerable 
vacuum,  he  opens  the  exhaust  valve  L  and  the  injection 
cock  at  the  same  time,  when  the  engine  will  probably 
commence  to  move  indoors,  the  piston  descending  in  the 
cylinder.  If  the  engine  does  not  move,  the  blowing 
through  must  be  repeated.  If  the  engine  be  lightly 
loaded,  or  if  there  be  but  little  water  in  the  pumps,  the 
regulator  valve  from  the  steam  pipe  (not  shown  in  the 
drawing)  must  only  be  opened  a  very  little  so  as  to 
supply  very  little  steam,  or  else  the  engine  is  liable  to 
make  its  in- door  stroke  with  much  violence,  and  perhaps 
do  mischief.  To  guard  against  such  accidents,  "catch- 
pieces"  similar  to  those  shown  at  c,  fig.  62,  but  reversed, 
are  often  fixed  on  the  main-rod  in  the  shaft,  and  other 


100  PRINCIPLES   OP   METAL   MINING. 

"  in-door  catch-pieces"  are  fixed  to  the  inner  end  of  the 
main  beam. 

125.  Working  the  Engine. — The  top  nozzle  G  contains 
three  valves,  only  one  of  which  is  shown  in  fig.  C7.  The 
valve  farthest  from  the  spectator  is  called  the  regulator 
valve.  This  guards  the  entrance  of  the  steam  pipe  from 
the  boiler,  it  is  only  occasionally  altered  by  the  engineer, 
being  opened  by  means  of  a  screw,  and  kept  open,  more 
or  less,  all  the  time  the  engine  is  working.  By  opening 
the  regulator  valve,  the  top  nozzle  is  kept  full  of  steam. 

Another  valve,  not  shown  in  the  figure,  is  the  steam 
valve;  this  is  situated  on  that  side  of  the  top  nozzle 
nearest  the  spectator.  The  steam  valve  is  opened  at  the 
commencement  of  each  stroke  of  the  engine,  when  the 
steam  passes  in  through  the  steam  port  F,  and  presses  on 
the  top  of  the  piston  and  forces  it  down,  so  making  the 
in-door  stroke.  In  Cornish  engines  the  steam  is  used 
expansively,  i.e.t  it  is  admitted  to  the  upper  part  of  the 
cylinder  at  a  high  pressure,  and  cut  off  by  closing  the 
valve  when  a  small  proportion  only  of  the  stroke  is 
made.  The  steam  already  in  the  cylinder  expands  until 
it  fills  it;  so  forcing  the  piston  to  the  bottom  of  the 
cylinder,  and  completing  the  in-door  stroke. 

The  equilibrium  valve  H  is  then  opened  and  the  ex- 
haust valve  L  closed,  the  steam  rushes  down  the  pipe  I, 
and  through  the  lower  port  J,  and  so  presses  upon  the 
lower  side  of  the  piston  as  strongly  as  upon  its  upper  side, 
thus  producing  equilibrium.  The  weight  of  the  pump  rods 
then  being  no  longer  overcome  by  the  steam  pressure  on 
the  upper  side  of  the  piston,  pulls  down  the  outer  end  D' 
of  the  beam,  and  the  engine  makes  her  out-door  stroke. 

It  must,  however,  be  borne  in  mind  that,  although  the 
steam  pressure  on  both  sides  of  the  piston  is  equal,  the 
steam  is  still  in  the  cylinder,  and  must  be  withdrawn  be- 
fore the  engine  can  make  another  stroke.  To  effect  this 
the  exhaust  valve  L  is  opened,  the  steam  rushes  along  the 
eduction  pipe  M  into  the  condenser  N.  Here  the  injec- 
tion cock  (not  shown  in  the  diagram)  is  opened,  a  jet  of 


MACHINERY  FOR  WORKING  PUMPS.        101 

cold  water  rushes  into  the  condenser,  and  the  steam  is  at 
once  condensed.  There  is  now  again  a  vacuum  under 
the  piston  and  in  the  equilibrium  pipe  I,  and  the  engine 
is  ready  to  make  another  stroke  as  soon  as  the  steam 
valve  is  opened. 

126.  Condenser. — The  condensation  of  the  steam  in  the 
condenser  N,  by  means  of  cold  water,  results  in  the  produc- 
tion of  a  quantity  of  hot  water.     There  is  also  a  quantity 
of  air  dissolved  in  the  water  and  mechanically  mingled  with 
it,  and  this  must  be  removed  or  the  efficiency  of  the  con- 
denser will  be  impaired.     The  hot  water,  air,  etc.,  pass 
through  the  foot  valve  O  into  the  lower  part  of  the  "  air 
pump "  P.     From  here  they  are  withdrawn  by  the  air 
pump,  the  rod  of  which  is  shown  at  r,  the  bucket  at  s, 
and  the  cover  valve  at  t.     The  upper  part  of  the  bucket 
is  sometimes  formed  by  a  large  circular  valve  as  shown; 
and  when  the  air  pump  rod  descends,  this  valve  opens 
and  allows  the  hot  water  and  air  to  pass  upwards  into 
the  hot  well  which  is  placed  at  the  upper  part  of  the  air 
pump.     When  the  bucket  rises  the  valve  closes,  and  the 
water,  etc.,  are  raised  and  delivered  through  the  cover  t, 
which  opens  to  permit  their  passage.     When  the  rod 
descends,  the  cover  valve  opens  again,  and  the  air  pump 
is  ready  for  another  stroke.     To  economise  fuel  the  hot 
water  so  raised  by  the  air  pump  is  accumulated  in  the 
upper  widened  part  of  the  air  pump  P',  from  which  it 
flows  under  the  plunger  of  the  hot  water  pump  u,  and  is 
forced  up  to  supply  the  waste  from  the  boiler. 

127.  Valve  Gear. — The  different  valves  are  worked  by 
tappets  placed  on  the  plug  rod  b,  but  the  small  scale  of 
the  drawing  does  not  allow  of  these  being  shown.    The 
speed  of  the  engine  is  regulated  by  means  of  the  "cataract" 
T,  which  is  placed  under  the  floor  w  w,  but  the  details  of 
which  are  not  shown.     All  the  valves  are  made  self- 
acting,  i.e.,  the  working  of  the  engine  is  made  to  open 
and  close  the  valves,  but  the  engineer  is  able,  by  modify- 
ing the  position  of  the  tappets,  and  in  other  ways,  to 
make  the  stroke  of  the  engine  as  few  as  one  in  several 


102  PRINCIPLES   OP   METAL   MINING. 

minutes,  or  as  many  as  13  or  14  in  one  minute  as  may 
be  required,  but  the  engine  works  most  economically 
when,  making  from  3  to  5  strokes  per  minute. 

A  pair  of  magnificent  engines  of  this  type  were  erected 
by  Messrs.  Harvey  &  Co.,  of  Hayle,  in  Cornwall,  for  the 
Tyne  collieries,  in  1869.  The  diameter  of  the  cylinders 
is  100  inches,  the  length  of  stroke  11  feet,  weight  of  main 
beam  40  tons,  and  the  total  weight  of  each  engine  nearly 
200  tons.  Such  great  masses  cause  the  first  cost  of  such 
machines  to  be  very  great,  but  this  is  more  than  made 
up  by  the  rarity  of  stoppages  for  repairs  and  the  daily 
economy  of  working. 

128.  Duty  of  Engines. — There  are  many  ingenious 
contrivances  in  connection  with  the  best  Cornish  engines, 
which  have  for  their  object  the  saving  of  fuel,  or  the  more 
perfect  working  of  the  engine.     These  cannot  be  described 
here,  but  the  result  of  their  combined  use  is,  that  several 
good  Cornish  engines  are  now  at  work  continuously,  both 
in  mines  and  in  water -works,  whose  "  duty"  averages 
nearly,  or  quite,  100,000,000  foot-lbs.,  or  in  other  words, 
which  lift  one  hundred  million  pounds  of  water  one  foot 
high,  by  the  consumption  of  each  hundredweight  of  coal. 

This  high  duty  is  obtained  when  the  engines  are  large, 
do  not  work  too  rapidly,  and  are  supplied  with  steam  at 
from  40  to  50  Ibs.  per  square  inch  pressure  from  an 
abundant  boiler  space.  Generally,  it  will  be  better  to 
use  an  additional  boiler  for  supplying  steam  in  prefer- 
ence to  forcing  those  already  in  use  beyond  their  capacity. 

129.  Compound  Engine. — A  different  mode  of  working 
steam  expansively  was  introduced  by  Arthur  Woolf,  many 
years  ago,  in  Cornwall,  and  after  being  worked  some  time 
by  Sims  and   others,  was  at   length  abandoned.     The 
mode  adopted  was  to  use  two  cylinders,  one  much  larger 
than  the  other;  the  small  one  placed  sometimes  above, 
sometimes  within,  the  larger.     Steam  at  high  pressure 
was  admitted  to  the  smaller  cylinder;  and,  after  doing  its 
work  there,  instead  of  being  discharged  to  the  condenser, 
was  allowed  to  flow  into  the  large  cylinder  where  it  ex- 


MACHINERY   FOR   WORKING    PUMPS.  103 

panded  so  as  to  fill  it,  at  the  same  time  pressing  down 
the  large  piston  with  a  certain  force.  The  motion  so 
produced  was  transmitted  through  the  piston-rod  to  the 
main  beam  of  the  engine,  and  from  there  to  the  pump 
rods  in  the  ordinary  manner. 

The  greater  complication  of  two  cylinders,  two  pistons, 
and  a  double  set  of  steam  passages,  led  to  the  abandon- 
ment of  this  mode  of  applying  steam  expansively  in 
favour  of  that  described  in  the  last  section,  but  a  modi- 
fication of  this  compound  engine  principle  is  now  being 
introduced  with  much  success  for  marine  and  stationary 
engines,  and  with  great  economy  of  fuel. 

130.  Boilers. — Among  the  boilers  most  suitable  for 
supplying  large  volumes  of  steam  continuously  at  the  pres- 
sure named,  may  be  mentioned  those  which  are  known 
as  the  "Cornish"  and  the  "Lancashire."  The  Trevithick 
or  Cornish  boiler  is  illustrated  in  figs.  68  and  69.  Fig. 
68  is  a  perspective  view  of  the  boiler,  fig.  69  is  a  section 


Fig.  G8.  Fig.  69. 

showing  the  mode  of  setting.  The  boiler  consists  of  a 
cylindrical  shell  made  of  boiler  plates  strongly  riveted 
together.  This  is  riveted  to  the  flat  ends,  and  the  angles 
strengthened  inside  by  "angle-irors."  A  cylindrical 
tube  is  riveted  in  the  same  manner  to  the  flat  ends,  but 
nearer  the  bottom  of  the  shell  than  the  top.  The  fire 
bars  are  placed  in  the  tube,  as  shown  at  a,  fig.  69,  and 
the  space  around  the  tube  is  filled  with  water  up  to  the 
water  line  b.  The  boiler  is  supported  by  masonry  en- 


104  tRlNCItLES  OF  METAL  MINING. 

closing  the  flues  at  c  c  and  d.  The  flames  and  heated  air 
produced  at  a  pass  along  the  boiler,  return  to  the  fire  end 
by  the  side  flues  c  c,  and  being  then  directed  into  the 
bottom  flue  d,  pass  along  under  the  boiler  to  the  chimney 
which  is  placed  at  the  far  end.  The  effect  of  this  ar- 
rangement is  that  most  of  the  heat  of  the  fire  is  imparted 
to  the  water  in  the  boiler  before  the  products  of  com- 
bustion make  their  escape  up  the  chimney  or  "  stack." 
Many  Cornish  boilers  are  made  from  30  to  40  feet  long, 
and  7  or  8  feet  wide,  with  a  fire  tube  from  3  feet 
6  inches  to  4  feet  6  inches  diameter;  and  some  large 
engines  require  as  much  steam  as  can  be  supplied  by 
three,  four,  or  even  six  of  such  boilers. 

When  large  boilers  of  the  Cornish  type  are  used,  it  is 
desirable  to  strengthen  the  fire  tube  by  rings,  transverse 
tubes,  or  in  some  other  manner. 

The  Lancashire  or  double  flued  boiler,  as  shown  in 
fig.  70,  is  really  a  modified  Cornish  boiler,  in  which  a 

somewhat  larger  heat- 
ing surface  is  obtained 
with  equal  water  and 
steam  space  without 
increasing  the  size  of 
the  outer  shell. 

131.     Clothing     of 
Boilers,  etc. — Much  of 
the    economy    of    the 
Cornish       system      of 
70.  pumping   is   no    doubt 

due  to  the  careful  manner  in  which  the  boiler,  steam 
pipes,  cylinders,  valves,  etc.,  are  encased  in  steam  jackets, 
or  clothed  with  felt,  sawdust,  or  other  non-conducting 
material.  In  many  cases  the  temperature  of  the  engine 
house  is  uniformly  below  90°,  except  in  very  hot  summer 
weather,  and  the  boiler  houses  are  but  little  warmer. 

132.  Quantity  of  Water  Raised. — The  quantities  of 
water  to  be  raised  in  some  mines  are  immense,  as  the  fol- 
lowing example  will  show. 


MACHINERY  FOR  WORKING  PUMPS.       105 

At  Mellanear  Copper  Mine,  near  Hayle,  by  no  means 
a  very  extensive  mine,  during  the  month  of  April,  1873, 
and  for  many  months  previously,  no  less  than  1 162  gallons 
of  water  per  minute  were  raised,  chiefly  from  the  bottom 
of  the  mine.  In  some  mines  the  quantity  raised  has 
reached,  for  short  periods,  the  enormous  quantity  of 
3000  gallons  per  minute.  In  1837,  the  late  Sir  Charles 
Lemon  estimated  the  quantity  of  water  raised  from  the 
mines  of  Cornwall  at  37,000,000  tons. 

133.  Direct  Acting  Pumps.  —  Within  the  last  few 
years  a  totally  new  mode  of  forcing  water  from  deep 
mines  has  been  adopted  in  some  districts  with  con- 
siderable success.  The  pumping  engine  is  placed  at  the 
bottom  of  the  mine  itself,  and  supplied  with  steam  by 
a  clothed  steam  pipe,  the  boilers  being  placed  above 
ground.  The  piston-rod  has  a  piston  at  one  end  and 
a  ram  at  the  other.  The  piston  works  in  the  steam 
cylinder,  the  ram  is  a  force  pump,  or  water  cylinder, 
which  communicates  with  the  sump  or  storage  cistern. 
From  the  force-pump  a  rising  main  proceeds  direct  to  the 
surface,  and  as  water  is  forced  by  the  motion  of  the  ram 
in  both  directions,  the  steam  is  constant  instead  of  being 
intermittent,  so  that  for  a  given  quantity  of  water  a 
smaller  diameter  of  pump  is  amply  sufficient.  These 
"direct  acting"  pumps,  as  they  are  called,  which  are 
made  by  Messrs.  Tangye,  Hay  ward  Tyler  &  Co.,  and 
others,  work  with  considerable  economy,  considering  that 
the  steam  is  used  non-expansively,  and  their  first  cost  is 
very  low;  the  chief  drawback,  in  districts  where  fuel  is 
cheap,  is  in  their  situation  at  the  bottom  of  the  mine,  since 
in  case  of  accident  the  engine  itself  would  be  drowned  out. 
It  is  therefore  necessary  to  have  these  pumps  in  dupli- 
cate, or  nearly  so,  or  a  serious  risk  is  encountered.  * 

One  of  these  pumps  was  used  for  a  long  time,  and  with 
much  success,  in  1872,  for  pumping  water  into  the  Morfa 
Colliery,  in  South  Wales,  in  order  to  put  out  a  great  fire 
which  resulted  from  a  most  disastrous  explosion, 


106  PRINCIPLES  OP   METAL   MINING. 

'CHAPTER  XVII. 

ON   ORE   DRESSING  OPERATIONS. 

134.  The  ores  having  been  brought  to  the  surface  by 
some  of  the  modes  described  in  Chaps.  XIII.,  XIV.,  it 
is  necessary  to  separate  them  from  the  worthless  material 
or  gangue.     To  some  small  extent  this  is  occasionally 
done  underground,  especially  in  the  case  of  the  ores  got 
by  tributers,  but  the  principal  part  of  the  separation  or 
"  dressing,"  as  it  is  called,  is  always  necessarily  done  at 
the  surface. 

The  dressing  operations  differ  much  in  the  case  of 
different  ores,  not  only  in  the  modes  adopted,  but  also 
in  the  more  or  less  complete  separation  of  the  veinstone, 
or  gangue.  Tin  ores  are  dressed  up  to  a  very  high 
standard,  often  so  as  to  yield  70  per  cent,  of  metal.  Lead 
ores,  as  commonly  sold,  contain  from  60  per  cent,  down- 
wards to  15  per  cent.  Copper  ores  from  18  or  20  down 
to  3  or  4  per  cent.  Manganese  ores  are  valued  according 
to  the  proportion  of  peroxide,  varying  from  50  to  90  per 
cent.;  a  standard  of  70  per  cent,  is  adopted,  and  the 
value  rises  much  more  rapidly  for  every  additional  per 
centage  of  peroxide  in  the  case  of  rich  than  of  poor 
ores.  Iron  ores  are  simply  spalled  and  hand-picked  in 
general,  and  yield,  as  sold,  from  25  to  65  per  cent,  of 
metal,  according  to  the  kind  of  ore.  Ores  of  gold,  silver, 
and  other  valuable  metals,  are  often  treated  by  a  combina- 
tion of  mechanical  and  chemical  operations,  sometimes  of 
a  highly  refined  character.  In  this  elementary  treatise,  we 
must  confine  ourselves  to  a  descriptive  outline  of  the  modes 
adopted  in  preparing  the  ores  of  tin  and  copper  for  the 
market  in  Cornwall,  and  of  silver  ores  in  South  America. 

135.  Tin  Ores. — The  ores,  if  in  large  masses,  are  first 
"spalled,"  or  broken  up  by  means  of  heavy  "spalling 
hammers,"  and  this  affords  an  opportunity  for  picking 
out  the  larger  portions  of  the  gangue.     Generally,  the 


ORE   DRESSING   OPERATIONS. 


107 


result  of  the  spalling  process  is  the  production  of  a  pile 
of  best  ore,  a  pile  of  seconds,  which  is  separately  treated 
in  its  further  stages,  and  a  pile  of  "deads/'  which  is 
thrown  away. 

Sometimes  after  spalling  the  ore  is  taken  at  once  to 
the  "stamps,"  but  occasionally  it  is  broken  or  "cobbed" 
still  smaller  by  means  of  lighter  "  cobbing  hammers,"  and 
this  gives  another  opportunity  of  hand  picking.  In  mines 
yielding  large  quantities 
of  stuff  of  even  quality, 
so  that  hand  picking  is  of 
little  avail,  the  spalling 
and  cobbing  processes  are 
now  sometimes  superseded 
by  the  use  of  a  stone 
breaker  or  crusher, 
"  Blakes"  being  preferred. 
The  economy  of  this,  when 
the  tin-stuff  is  hard,  is 
very  considerable,  pro- 
bably about  one-half,  since 
the  cost  of  hand  spalling 
is  from  6d.  to  8d.  a  ton, 
while  the  stone  breaker 
will  do  the  same  work  for 
3d.  or  4d.,  which  sum  in- 
cludes a  full  allowance 
for  depreciation  of  the 
machinery,  and  interest 
on  its  first  cost. 

136.  Stamps.— The  ore 
being  broken  down  about 
the  size  of  road  stone,  is 
now  in  a  fit  state  for  the 
action  of  the  "stamps." 
Those  in  ordinary  use  are 
shown  in  figs.  71  and  72.  The  ore  is  tipped  on  to 
the  slope  D,  fig.  72,  and  gradually  makes  its  way  down 


103 


PRINCIPLES   OF   METAL   MINING. 


under  the  heavy  stamp  heads  A.  These  stamp  heads, 
weighing  from  4  to  6  cwt.  each,  figs.  71,  72,  are  lifted 
successively  by  means  of  the  lifters  B,  and  the  cams  c  on 
the  revolving  axle  H,  to  a  height  of  10  or  12  inches, 
and  falling  on  the  ore  speedily  reduce  it  to  fine  powder. 
Water  is  continually  falling  upon  the  ore  from  a  "  launder," 
as  shown  in  fig.  7 1 ,  and  this  facilitates  the  escape  of  the 
fine  particles  of  ore  through  the  gratings  or  "stamp 
grates,"  G  G.  Taking  the  county  of  Cornwall  throughout, 
the  average  weight  of  the  stamp  head  and  lifter  will 
perhaps  be  4  cwt.,  the  number  of  blows  per  minute 
about  40,  and  the  amount  of  stuff  stamped  not  far  from 
1  ton  per  head  in  each  24  hours.  The  average  consump- 
tion of  fuel,  when  steam  engines  are  used,  is  about  1J 
cwt.  per  ton  of  stuff. 


Fig.  72. 


In  the  copper  mines  of  Lake  Superior,  in  the  silver 
mills  of  Nevada,  and  in  the  gold  fields  of  Australia,  much 


ORE   DRESSING   OPERATIONS. 


109 


heavier  stamps  are  in  use,  in  some  instances  nearly  a  ton 
each,  and  the  work  got  through  is  increased  in  an  even 
greater  proportion,  but  special  contrivances  are  necessary 
to  guard  against  "  over-stamping,"  by  providing  for  the 
free  exit  of  the  ore  as  fast  as  it  is  sufficiently  reduced, 
as,  if  this  is  not  done,  a  large  amount  of  "slime"  ore  is 
produced,  resulting  in  much  loss  of  ore  in  the  subsequent 
dressing  processes. 


Fig.  73. 

137.  Buddling. — The  finely-powdered  ore,  passing  from 
the  stamp  grates,  is  treated  in  a  variety  of  ways,  in  bud- 
dies, frames,  kieves,  etc.,  but  the  aim  and  end  of  all 
these  operations  is  the  same,  viz.,  the  separation  by  the 
action  of  gravity  of  the  heavy  ore  from  the  lighter 
waste,  the  different  specific  gravities  being  aided  by 
partially  suspending  the  ore  in  water.  In  the  present 
treatise  we  can  do  little  more  than  describe  one  of  these 
processes,  that  of  "huddling."  Fig.  73  is  a  section  of  the 
ordinary  convex  buddle.  E  E  is  a  circular  pit  about  18 
or  20  feet  in  diameter,  and  2  feet  6  inches  deep  at  the 
sides.  F  is  a  raised  table,  5  or  6  feet  in  diameter,  highest 
in  the  centre,  and  sloping  outwards  in  all  directions;  the 
floor  of  the  pit  E  E  also  slopes  outwards  as  shown.  The 
stamped  ore  suspended  in  water,  forming  a  very  thin  mud, 
passes  in  the  direction  of  the  arrows  into  the  hopper  at  A, 
and  is  strained  through  a  grating  which  keeps  back  any 
chips  of  wood  or  coarse  waste  which  may  have  got  into 
the  channel.  The  ore  passes  down  the  channel  A  in  the 


110  PRINCIPLES  pP  METAL  MINING, 

direction  of  the  arrow,  and  flows  into  the  cup  B  of  the 
central  table,  and  from  here  is  distributed  by  six  or  eight 
openings  or  channels  over  the  central  table,  and  from  here 
over  the  floor  E  of  the  buddle.  D  D  are  brushes  four 
or  six  in  number,  which  revolve  and  spread  the  ore  evenly 
over  the  floor  of  the  buddle.  The  whole  is  moved  by  the 
level  wheels  I,  by  means  of  shafting  SJSf  communicating 
with  a  water  wheel,  or  some  other  source  of  power.  It 
is  found  that,  by  buddling  the  stamped  tin-stuff  in  this 
way,  the  heavier  particles  of  ore  mostly  accumulate  near 
the  central  table,  while  the  waste  is  chiefly  carried  by 
the  flowing  water  to  the  circumference.  The  buddle 
being  full,  the  outer  portion  is  thrown  aside  or  buddled 
over  again,  and  the  central  portion  in  like  manner  is 
treated  by  itself,  either  by  repeating  the  same  process  or 
slightly  varying  it.  Other  forms  of  buddies  are  in  use;  in 
some  the  central  part  is  made  lower  than  the  outside,  and 
the  ore  is  supplied  around  the  circumference,  but  the 
principle  of  all  buddies  is  the  same. 

The  "frames"  are  sloping,  wooden  trays  often  self- 
acting,  and  generally  used  for  dressing  very  fine  ores  or 
"  slimes."  The  ore  is  made  to  run  down  the  slope,  when 
the  richer  portions  remain  on  the  wooden  surface  of  the 
frame,  while  the  light  waste  is  carried  away  by  the  water. 
These  richer  portions  are  at  intervals  washed  into  separate 
receptacles  by  a  sudden  flush  of  water. 

When  the  ore  is  thus  rendered  tolerably  pure,  it  is 
placed  in  quantities  of  several  cwts.  in  a  large  tub  or 
"kieve"  and  well  stirred  up  with  water.  It  is  then 
allowed  to  settle,  while  a  continual  vibration  is  produced 
by  knocking  with  hammers  against  the  sides  of  the  kieve. 
When  at  last  the  ore  has  all  settled  down,  the  water  is 
poured  away,  and  the  upper  layers  of  the  deposit  are 
scraped  off  and  put  aside  for  further  treatment,  as  they 
contain  nearly  all  the  remaining  impurity.  This  opera- 
tion is  called  "  tossing  "  or  "  tozing,"  and  the  ore  is  now 
ready  for  sale  as  "  black  tin." 

138.  Calcining.— The  methods  just  described  are  suffi- 


ORE  DRESSING  OPERATIONS.  Ill 

cient  when  the  water  is,  as  is  usually  the  case,  much 
lighter  than  the  ore.  Sometimes,  however,  the  waste 
consists  of  pyrites,  mispickel,  or  some  other  metallic 
mineral,  when  an  additional  operation  is  necessary,  called 
" burning"  or  calcining.  The  partially  dressed  ore  is 
placed  in  a  furnace  and  strongly  heated.  By  this  heating 
the  oxide  of  tin  is  not  changed,  but  the  pyrites  or  mis- 
pickel gives  off  its  sulphur  or  arsenic  as  a  thick  smoke, 
and  is  changed  into  oxide  of  iron,  which  being  much 
lighter  than  oxide  of  tin,  is  readily  washed  away  by 
the  huddling  or  other  dressing  operations.  The  fumes  of 
sulphur  or  arsenic  are  condensed  in  long  flues,  from 
which  they  are  collected  at  intervals  and  sold. 

In  the  various  processes  a  quantity  of  material  of  a 
mixed  nature,  called  "  dredge,"  or  "  roughs,"  or  "  rows," 
is  often  separated,  011  the  one  hand  from  the  rich  ore,  and 
on  the  other  from  the  worthless  waste.  These  "  rows," 
when  examined  under  the  microscope,  are  seen  to  be  of  a 
compound  nature,  consisting  of  particles  of  ore  attached 
to  particles  of  waste.  In  order  to  separate  these  different 
materials,  it  is  necessary  to  reduce  the  "  rows  "  to  a  very 
fine  powder,  and  this  is  best  done  by  machines  called 
"  pulverisers."  The  material  to  be  treated  is  mixed  with 
water,  and  ground  between  plates  of  iron  moving  rapidly 
in  opposite  directions,  after  which  it  is  dressed  on  buddies 
or  on  frames  like  the  "  slime  "  ores  already  mentioned. 

139.  Copper  Ores  are,  in  the  first  instance,  spalled, 
cobbed,  and  hand-picked,  as  already  described  in  the  case 
of  tin  ores,  and  divided  into  "  best  work  "  and  "  seconds," 
which  are  treated  separately  in  the  subsequent  processes. 
They  are  then  passed  into  the  crusher,  which  consists  of 
two  short  and  heavy  rollers  of  chilled  iron,  moving  in 
opposite  directions,  and  kept  in  contact  by  means  of  a 
weighted  lever.  The  ore  is  fed  into  the  crusher  through 
a  hopper,  and  in  passing  between  the  rollers  is  broken 
into  small  fragments.  The  crushed  ore  passes  into  a 
revolving  cylindrical  sieve  or  riddle,  the  wires  of  which 
are  about  J  or  f  of  an  inch  apart,  and  the  pieces  which 


112  PRINCIPLES  OF  METAL  MINING. 

are  too  lai'ge  to  pass  through  are  returned  to  the  hopper. 
The  best  ore  when  so  crushed  is  ready  for  sale,  but  the 
seconds  has  next  to  be  "jigged."  In  this  process  the  ore 
is  spread  over  the  bottom  of  a  large  rectangular  sieve, 
the  wires  of  which  are  from  \  to  \  of  an  inch  apart. 
The  sieves  are  made  to  move  up  and  down  for  a  few 
minutes  with  a  peculiar  jerking  motion  while  dipping  in 
water.  The  fine  particles  which  pass  through  the  sieve 
are  sometimes  buddled,  sometimes  sold  without  further 
treatment.  The  effect  of  the  jigging  upon  that  which 
remains  in  the  sieve,  is  to  cause  the  richer  particles  of 
ore  to  form  a  layer  near  the  bottom,  the  lighter  waste  rest- 
ing upon  it.  This  is  scraped  off  and  thrown  away,  or 
put  aside  for  further  treatment,  but  the  lower  layer  is 
found  to  be  so  much  enriched  as  to  be  now  ready  for  sale. 

140.  Lead  Ores  are  usually  dressed  to  a  higher  standard 
than  copper  ores,  but  the  mode  adopted  is  very  similar. 
The  slimes  are  ground  and  buddled,  and  treated  like  tin  ores. 

141.  Sampling  and  Assaying. — Tin,  copper,  and  lead 
ores  are  often  got  by  tributers  as  already  mentioned, 
and  in  such  cases  it  is  necessary  to   carefully  sample 
the  piles  or  "  doles "  belonging  to  the  different  parties 
before  they  are   thrown  together  for  dressing.       The 
mode  of  doing  this  is  as  follows: — The  whole  heap  is 
first  well  mixed,  and  then  divided  into  four  equal  por- 
tions.     One  of  these  portions  is  taken,  and  all    the 
large  pieces  are  broken  up  small,  spalled,  and  cobbed, 
and  again  well  mixed.      From  this  another  fourth  is 
taken  and  broken  still  smaller,  and  again  mixed  and 
divided,  and  these  operations  are  continued  until  the 
portion  operated  is  reduced  to  a  fine  powder.     A  weighed 
or  measured  portion  of  this  is  then  taken  for  or  by  the 
sampler  for  assay.     If  a  tin  ore,  the  produce  is  at  once 
determined  by  the  process  of  vanning,  and  sometimes 
this  mode  is  adopted  for  copper  or  lead  ores.     More  com- 
monly, however,  these  are  assayed  by  heating  in  a  clay 
crucible  with  the  proper  fluxes,  and  the  tributers  are 
paid  for  the  whole  pile,  which  is  weighed  before  being 


ORE  DRESSING  OPERATIONS.  113 

dressed,  according  to  the  result  of  the  assay.  In  general 
the  tributers  find  it  is  to  their  advantage  to  divide  their 
piles  into  two,  separating  the  best  work  from  the  seconds, 
when  each  portion  is  of  course  separately  assayed. 

142.  Gold  and  Silver  Ores,  Amalgamation.— Gold  very 
frequently  occurs  in  the  state  of  metal,  when  it  is  usually 
separated  by  stamping,  and  a  series  of  washings  somewhat 
like  the  mode  adopted  in  dressing  tin.  Both  gold  and 
silver,  however,  often  occur  in  small  proportions,  chemi- 
cally combined  with  other  substances,  when  the  process  of 
amalgamation  is  adopted  for  their  separation.  At  Chon- 
tales  Mine,  in  Nicaragua,  the  gold  and  silver  ore  is  first 
stamped  fine,  and  then  allowed  to  pass  successively  over 
amalgamated  copper  plates,  "rimes,"  or  small  stony 
channels  containing  mercury,  channels  or  boxes  filled 
with  mercury  and  blankets,  and  finally  through  a  copper 
plated  launder  into  a  rectangular  buddle.  The  plates  are 
prepared  by  first  washing  with  nitric  acid  and  then  rub- 
bing with  mercury,  a  little  sodium  being  added  to  the 
mercury  to  increase  its  attraction  for  the  precious  metals. 

The  plates  are  scraped  every  twelve  hours,  and  the 
amalgam  so  obtained,  as  well  as  that  found  in  the  riffles 
and  mercury  boxes,  is  washed  with  water  to  clear  it  from 
all  grease,  sand,  or  other  impurity.  All  the  washings  of 
the  first  amalgam,  the  washings  of  the  blankets  and  the 
stuff  from  the  head  of  the  buddle  are  then  ground  fine  in 
the  "  arrastre  "  or  "  tahona,"  a  rude  mill  of  rough  stones 
worked  by  mules,  mercury  is  added  from  time  to  time, 
and  the  amalgam  so  obtained  is  added  to  the  first  portion. 
The  whole  is  then  squeezed  through  sail  cloth  or  leather 
to  separate  any  excess  of  mercury,  and  the  remaining 
amalgam  is  placed  in  an  iron  retort  and  strongly  heated. 
The  mercury  from  the  amalgam  passes  away  as  vapour, 
and  is  condensed  in  vessels  of  cold  water  for  future  use, 
and  the  alloy,  gold  and  silver,  remaining  in  the  retort,  is 
run  into  bars  for  sale;  these  metals  being  afterwards 
separated  from  each  other  by  a  separate  chemical  process. 
In  Mexico  it  is  the  practice  to  grind  the  ores  very  finely 
18B  II 


114  PRINCIPLES  OP  METAL  MINING. 

with  mercury  or  amalgam  in  arrastres,  after  which  a  crude 
sulphate  of  copper  obtained  by  roasting  copper  pyrites  is 
added,  together  with  common  salt  and  more  mercury,  and 
the  whole  being  well  mixed  is  left  to  a  kind  of  fermenta- 
tion for  several  days,  when  the  amalgam  is  separated  by 
washing  and  the  mercury  separated  in  the  manner  already 
described. 

143.  Many  modifications  of  this  amalgamation  process 
are  adopted  in  different  mines,  districts,  or  countries;  but 
the  broad  outlines  of  the  process  are  everywhere  the 
same.  The  loss  of  mercury  is  considerable,  but  varies 
from  half  an  ounce  for  each  ounce  of  the  precious  metal 
obtained  up  to  four  or  five  times  that  quantity. 


CHAPTER  XVIII. 

ON  THE  VENTILATION  AND  LIGHTING  OF  UNDERGROUND 
WORKINGS. 

144-.  Nature  of  Air. — No  miner  can  be  too  much  im- 
pressed with  a  sense  of  the  great  importance  of  good 
ventilation.  The  air  we  breathe  consists  mainly  of  two 
gases  called  by  chemists  "oxygen"  and  "nitrogen." 
These  are  mingled  together  in  the  proportion  of  about 
one  part  oxygen  to  four  parts  nitrogen.  It  is  the  oxygen 
which  is  really  necessary  for  the  support  of  life,  while 
the  office  of  the  nitrogen  is  to  dilute  it  and  to  increase 
its  volume.  The  air  being  taken  into  the  lungs  in  the 
act  of  breathing,  the  oxygen  combines  with  some  spent 
carbon  from  the  blood,  and  is  thereby  converted  into 
"  carbonic  acid,"  or  as  it  is  sometimes  called  "  carbonic 
anhydride."  Carbonic  acid  is  injurious  when  breathed, 
even  if  it  is  mixed  with  a  large  volume  of  pure  air,  and 
it  should  therefore  be  removed  as  fast  as  it  is  formed. 
When  men  work  in  the  open  air  the  carbonic  acid  formed 
is  speedily  dispersed,  and  as  the  supply  of  pure  air  is 


VENTILATION"   OP   UNDERGROUND   WORKINGS.         115 

abundant,  no  ill  effect  follows.  But  it  is  otherwise  in 
rooms,  and  especially  in  mines;  here  the  air  soon  becomes 
quite  unfit  for  use  if  it  be  not  constantly  renewed,  hence 
the  necessity  for  ventilation. 

The  impurities  imparted  to  the  air  by  breathing  are 
much  increased  in  mines  by  the  constant  use  of  candles 
or  lamps,  rendered  necessary  by  the  absence  of  daylight, 
and  by  the  explosion  of  powder  or  other  agents  used  for 
blasting.  In  some  iron  mines,  carbonic  acid  is  given  oft' 
in  large  quantities  by  the  ore  as  it  is  broken,  and  in 
many  metal  mines,  where  iron  pyrites  is  abundant,  the 
air  is  speedily  deprived  of  its  oxygen  and  rendered  unfit 
for  use,  and  incapable  of  sustaining  life  by  the  oxidation 
of  the  pyrites  which  is  continually  going  on.  In  coal 
mines,  inflammable  gases  called  "  fire-damp "  are  often 
given  off  in  great  abundance,  but  such  gases  are  very 
seldom  met  with  in  metal  mining,  except  in  coal  districts. 

The  miner  has  always  a  good  test  at  hand  for  the  fit- 
ness of  the  air  he  is  breathing.  If  his  candle  burns 
brightly  and  well  the  air  is  fit  to  breathe,  but  if  he  has 
great  difficulty  in  keeping  it  alight  when  the  air  is  still, 
or  if  the  flame  becomes  larger  and  of  a  pale  blue  colour, 
and  flickers  greatly  or  goes  out,  the  air  which  does  not 
properly  support  combustion  will  not  support  life,  and 
some  artificial  means  of  ventilation  becomes  necessary,  or 
the  miner's  health  will  give  way. 

This  test  is  much  more  reliable  than  the  common  mode 
of  judging  by  the  rapidity  of  the  current  at  any  given 
point,  as  it  may  be  applied  in  the  working  "  ends "  or 
"  faces  "  themselves  where  the  air  is  often  stagnant,  not- 
withstanding that  there  is  a  good  current  in  some  of  the 
drifts. 

145.  Ventilation  may  be  either  natural  or  artificial. 
In  coal  mines  it  is  almost  always  artificial,  in  metal 
mines  it  is  in  a  majority  of  instances  natural.  Some- 
times, however,  the  naturally  produced  current  of  air  is 
improved  and  guided  by  air  stoppings,  doors,  or  other 
means  as  may  be  found  necessary,  and  in  some  few 


116         .  PRINCIPLES   OF   METAL   MINING. 

instances  an  entirely  artificial  mode  has  to  be  adopted, 
especially  while  sinking  shafts  or  driving  long  levels. 

Unless  the  shaft  be  very  deep,  a  simple  division  of 
thin  wood  or  painted  canvas,  dividing  the  shaft  from 
top  to  bottom  into  two,  will  often  be  found  sufficient. 
The  men  working  in  the  shaft  on  one  side  of  the  parting 
will  raise  the  temperature  somewhat,  when  it  will  be 
converted  into  an  upcast,  while  the  cool  air  will  descend 
011  the  other  side  or  downcast  to  supply  its  place. 

146.  Air  Sollars.— A  natural  current  may  often  be  pro- 
duced in  a  long  level  by  means  of  an  "  air-sollar."     To 
form  an  air-sollar,  the  floor  of  the  level  carrying  the  tram 
road  is  laid  about  6  inches  above  the  actual  bottom  of 
the  level,  and  is  supported  by  cross-sleepers  resting  upon 
blocks  of  wood  or  stones,  or  the  floor  in  the  centre  of 
the  level  may  be  excavated  somewhat  deeper  than  the 
sides.     Planks  are  laid  over  the  sleepers  just  mentioned 
to  form  a  kind  of  deck,  and  the  whole  is  rendered  air- 
tight  by  plastering  with  mud.      This  will    divide  the 
tunnel  into  two  very  unequal  portions.     Through  the 
lower  division  or  air-sollar,  a  current  of  cool  and  there- 
fore heavy  air  will  pass  into  the  end,  and  this  will  be 
further  cooled  if  there  be  water  issuing  from  the  lode  at 
any  points.     The  air  heated  by  the  breathing  of  the  men, 
the  heat  of  the  candles,  etc.,  will  pass  out  through  the 
level  itself,  and  so  a  constant  current  will  be  kept  up. 
The  "level"  should  be  kept  as  truly  level  or  "dead"  as 
possible  for  several  reasons,  two  of  which  may  be  men- 
tioned here :  1st,  if  there  be  water  flowing  out  through 
the  level,  and  the  fall  be  considerable,  the  rapidity  of  the 
current  of  water  will,  to  some  extent,  check  the  ingoing 
current  of  air;  2nd,  if  the  level  rise  rapidly,  the  floor  of 
the  end  will  soon  be  at  a  higher  actual  level  than  the 
"  back  "  of  the  entrance,  when  the  heated  air  will  actually 
have  to  descend  in  order  to  make  its  escape,  although  the 
natural  tendency  of  heated  air  is  always  to  ascend. 

147.  Should  it  be  necessary  to  do  more  than  divide  the 
ehaft,  or  air-sollar  the  levels,  the  mode  known  as  pipe 


VENTILATION  OF  UNDERGROUND  WORKINGS.         117 


and  cap-head,  which  is  similar  to  that  which  is  so  com- 
monly  vised  on  board  ship,  may  be  resorted  to.  This  is 
effected  as  follows.  A  pipe  of  thin  metal  or  1"  wood  is 
made  of  about  1  square  foot  area  or  less,  to  which  is 
fitted  a  revolving  cap-head  a,  fig. 
74.  The  lower  end  of  the  pipe  is 
carried  down  to  the  bottom  of  the 
shaft,  and  the  open  mouth  b  is 
turned  towards  the  wind.  A  cur- 
rent of  fresh  air  is  thus  forced 
down  to  the  bottom  of  the  shaft 
where  the  men  are  at  work,  and 
thus  displaces  the  foul  air,  forcing 
it  up  the  shaft.  In  Cornwall,  for  Fig.  74. 

temporary  purposes,  the  writer  has  seen  a  zinc  rain-water 
pipe  so  arranged  with  a  miner's  jacket  extended  by  wires 
at  the  top  for  a  "  cap-head  "  or  "  sail."  A  similar  arrange- 
ment may  be  adopted  for  ventilating  a  level,  the  pipe 
being  carried  into  the  end,  but  sharp  angles  in  the  pipe 
should  be  avoided  as  much  as  possible.  It  is  plain,  how- 
ever, that  this  mode  of  ventilation  can  only  be  adopted 
when  the  wind  is  blowing,  but  in  time  of  calm,  under- 
ground ventilation  is  most  of  all  wanted.  To  meet 
this  difficulty,  a  small  fan  may  be  placed  in  the  upper 
end  of  the  pipe,  worked  by  hand,  a  water  wheel,  or  a 
steam  engine,  and  arranged  either  to  force  pure  air  into 
the  workings,  or  still  better,  to  draw  the  impure  air  out, 
leaving  the  pure  air  to  find  its  way  down  the  shaft. 

In  many  cases  a  jet  of  high  pressure  steam  from  a 
boiler  may  be  discharged  into  the  upper  end  of  the  pipe, 
when  an  outward  current  will  be  at  once  set  up. 

148.  The  Water  Trompe. — Where  there  is  a  supply 
of  water  at  surface,  and  an  adit  level  to  carry  away 
the  waste,  the  water  "trunk,"  or  "trompe,"  may  be 
used  for  ventilation  with  much  advantage.  If  there 
be  no  adit,  and  the  spent  water  would  have  to  be 
pumped  up  again  after  use,  it  may  be  better  to  apply 
the  power  directly  to  produce  a  current  of  air  by 


115 


PRINCIPLES  OP  METAL  MINING?. 


means  of  a  fan  or  air  pump,  unless  there  be  a  sur- 
plus of  pumping  power.  Figs.  75,  76  snow  two  forma 
of  the  water  trompe.  In  fig.  75  the  water  from  the 
launder  a  falls  upon  the  series  of  iron  bars  6,  and  down 
the  pipe  c  into  the  cistern  d.  The  stream  of  water  being 
broken  by  the  bars,  a  quantity  of  air  is  entangled  and 
carried  down  with  it,  and  this  escapes  at  the  trunk  or 
exit  pipe  e.  The  water  overflows  the  cistern  d  and  is 
pumped  up  again,  or  passes  away  by  an  adit  level.  In  fig. 
76,  the  water  enters  the  hopper  by  the  launder  at  passes 


Fig.  75.  Fig.  70. 

down  the  pipe  c,  and  falls  upon  the  dash-block  f,  placed 
in  the  cistern  d,  the  overflow  of  which  is  at  g.  Air  is 
drawn  into  the  pipe  c  through  the  holes  b,  and  makes  its 
exit  as  before  at  e.  By  lengthening  the  exit  pipe  so  as 
to  reach  into  the  "end"  of  a  level,  these  modes  may  be 
made  available  for  ventilating  very  long  drifts.  In  all 
cases  the  exit  pipe  should  be  large,  as  it  is  quantity 
rather  than  a  rapid  current  which  is  wanted,  and  sharp 
angles  should  be  avoided  as  much  as  possible,  since  the 


VENTILATION  OF  UNDERGROUND  WORKINGS. 

air  current  receives  a  serious  check  at  every  sudden 
change  of  direction. 

149.  Natural  Ventilation.  —  In  working  lodes  to  a 
moderate  depth,  the  difference  of  level  of  the  "  braces" 
of  the  different  shafts,  due  to  the  irregularities  of  the 
surface,  is  often  sufficient  to  determine  the  direction 
of  the  current  of  air,  and  to  produce  a  good  natural 
ventilation,  although  it  is  sometimes  necessary  to  use 
air  partings  or  stop  doors  to  aid  this.  Thus,  if  in  a 
mine,  situated  as  in  fig.  77,  there  be  two  shafts,  ab, 


ig.  77. 

the  current  will  be  in  the  direction  of  the  arrows 
when  the  surface  temperature  is  warmer  than  that  of 
the  bottom  of  the  mine,  and  it  will  be  reversed  when 
the  surface  temperature  is  lower.  Whenever  the  sur- 
face temperature  is  the  same  as  that  of  the  bottom  of 
the  mine,  the  ventilation  will  be  likely  to  suffer;  but 
this  state  of  things  will  not  last  many  hours  at  any  one 
time,  since  the  temperature  of  the  bottom  of  the  mine 
will  be  constant,  that  of  the  surface  rapidly  variable.  It 
may  be  necessary  to  place  regulating  doors  at  &  6  and  c  c, 
bb  being  shut  when  cc  are  opened,  and  vice  versd.  At 
d  the  current  will  be  divided  as  shown.  The  level  at  e 
will  be  very  badly  ventilated  unless  a  current  of  air  can 
be  sent  along  it  by  means  of  an  air-sollar,  or  in  some 
similar  manner.  Sometimes  a  chimney  is  built  over  one 


120  I'lllNCIPLES  OF  METAL  MtftltfG. 

shaft  to  increase  the  natural  inequality  of  level,  and  to 
assist  in  the  determination  of  the  current.  This  should 
be  of  large  area,  as  if  small,  a  sufficient  quantity  of  air 
will  not  pass. 

In  very  deep  mines  the  difference  to  be  obtained  by 
means  of  a  high  chimney  is  very  slight  as  compared  with 
the  whole  depth  of  the  shaft,  but  the  naturally  high 
bottom  temperature  of  such  mines  greatly  assists  their 
ventilation  by  means  of  natural  currents. 

150.  Heat  of  Deep  Mines. — The  rate  of  increase  of 
temperature  in  deep  mines  varies  much  in  different 
localities.  In  some  places  it  has  been  found  as  much  as 
1°  F.  for  each  45  feet  in  depth,  in  others  little  more 
than  half  this  rate.  After  about  the  first  10  fathoms  the 
variations  of  surface  temperature  have  no  effect  on  that 
of  the  mine  below,  which,  in  the  absence  of  chemical 
changes  or  of  hot  springs,  is  always  almost  exactly  the 
same.  One  exception,  however,  must  be  noted.  In  deep 
workings,  when  they  are  first  opened,  the  temperature  is 
often  much  higher  than  in  the  same  situations  after 
several  months'  working.  Thus,  at  the  Clifford  Amalga- 
mated Copper  Mines,  in  Gwennap,  the  air  in  the  220 
fathom  level  was  100°  F.  in  1863;  but  in  July,  1864, 
it  had  sunk  to  83°.  In  the  230  fathom  level  then  just 
opened  the  temperature  at  the  same  date,  July,  1864, 
was  104°  F. 

At  the  Duckinfield  Colliery,  in  Durham,  the  tempera- 
ture was  found  to  increase  from  a  depth  of  20  feet  down 
to  358  J  fathoms,  at  an  average  rate  of  1°  F.  for  each 
88  feet  in  depth.  At  the  Rose  Bridge  Colliery,  near 
Wigan,  from  a  depth  of  80 \  fathoms  to  403  fathoms,  the 
average  increase  was  at  the  rate  of  1°  in  each  67  feet. 
This  latter  is  one  of  the  deepest  mines  yet  worked. 

Perhaps  the  greatest  depth  yet  attained  is  at  Viviers 
Reunis,  near  Gilly,  in  Belgium,  where  the  shaft  itself 
reaches  a  depth  of  3411  feet,  or  nearly  570  fathoms,  and 
the  bottom  of  a  trial-staple  was  found  by  Mr.  "VV.  W. 
Smyth,  in  1871,  to  be  3489  feet,  or  58U  fathoms. 


VENTILATION  OP   UNDERGROUND  WORKINGS.        121 

Furnaces,  air  pumps,  or  powerful  steam  jets  are  seldom 
required  in  the  ventilation  of  metal  mines,  unless  they 
are  situated  in  coal  districts,  or  worked  in  connection 
with  coal  mines.  The  construction  and  mode  of  working 
will  be  fully  described  in  the  elementary  treatise  on  "  Coal 
Mining,"  forming  part  of  this  series.  •  * 

151.  Lighting  of  Workings. — In  the  metal  mines  of 
Cornwall,  South  Wales,  and  the  north  of  England,  the 
usual  mode  of  lighting  the  mines  while  at  work  under- 
ground is  by  means  of  tallow  candles.     Each  man  carries 
a  tallow  candle  in  his  hand  while  walking  along  the 
levels,  using  a  lump  of  clay  as  a  convenient  holder.     The 
same  lump  of  clay  serves  to  fix  the  candle  to  his  hat, 
while  he  is  ascending  or  descending  the  shaft,  and  to 
attach  it  to  the  rock  in  a  convenient  position  when  the 
place  of  work  is  at  length  reached.     The  candles  used  in 
Cornwall  have  large  wicks,  so  that  a  sudden  current  of 
air  may  not  too  readily  extinguish  them;  and  there  are 
from  12  to  16  to  the  pound.     In  the  north  of  England 
the  candles  used  go  from  20  to  30  to  the  pound;  and 
formerly  much  thinner  candles  than  these  were  used,  but 
such  very  small  candles  are  now  seldom  seen, 

152.  Lamps. — In  some  of  the  mines  of  the  north 
of  England,  South  Wales,  and  Scotland,  and  in  Saxony 
and  other  parts  of  Germany,  small  metal  lamps  are 
used,  in  which  colza,  rape,  or  other  oil  is  burnt.     These 
lamps  are  made  with  a  small  hook  for  attachment  to 
the  miner's  hat,  and  a  spike  which  may  be  placed  in 
a  joint  of  the  rock  when  the  place  of  work  is  reached. 
The  light  given  by  such  lamps  is  not  equal  to  that 
of  good  candles,  and  this  is  probably  the  reason  why 
they  have  not  found  favour  in  Cornwall;  but  the  cost 
does  not  exceed  from  f d.  to  Id.  per  shift  or  core  of 
eight  hours,  which  is  about  one-half  the  cost  of  candles. 
Within  the  last  few  years,  lamps  for  burning  paraffin 
and  petroleum  oils  underground  have  been  devised.     The 
author  has  not  seen  any  of  them;  but  they  are  well  spoken 
of,  as  they  give  a  good  light  at  little  cost.      Hitherto, 


122  PRINCIPLES   OP   METAL  MINING. 

however,  they  have  not  been  made  to  burn  without  much 
more  smell  than  either  oil  lamps  or  candles. 

153.  Coal  gas  was  first  utilised  in  Cornwall,  by  Murdoch, 
in  or  about  1792,  when  he  lit  up  his  workshops  at  Red- 
ruth  with  gas.  He  had  previously  been  in  the  habit  of 
carrying  a  bladder  full  under  his  arm,  which  supplied  a 
lighted  jet  in  his  night  journeys  across  the  moors  of 
Cornwall,  to  the  great  alarm  of  the  country  folk.  Two 
mines  at  least  have  been  lighted  with  gas  at  different 
periods  in  Cornwall,  but  at  present  no  gas  is  used  for 
this  purpose  in  the  county.  At  Tresavean  Mine,  early 
in  the  present  century,  gas  was  used  for  lighting  the 
shafts  and  some  of  the  principal  workings.  The  latest 
instance,  however,  was  at  Balleswidden,  about  the  year 
1866,  when  gas  was  carried  down  the  shaft  and  into  the 
levels  and  pitches  where  the  men  were  at  work,  as  far  as 
the  120  fathom  level.  Where  four  men  were  at  work  one 
gas  jet  was  found  to  give  sufficient  light  for  all,  with  less 
smoke  and  unpleasant  smell  than  candles.  The  cost  was 
officially  reported  to  be  only  one-third  that  of  candles; 
but  for  some  reason  or  other  the  apparatus  was  ultimately 
removed.  Coal  gas  is  extensively  used  for  lighting  mines 
of  all  kinds  in  the  north  of  England.  Sometimes  it  is 
made  at  the  surface,  stored  in  a  gasometer,  and  sent  down 
by  means  of  a  fan  blower,  steam  jet,  turbine,  or  a  water 
trompe.  A  current  having  a  force  equal  to  a  pressure 
of  10  or  12  inches  of  water  is  found  sufficient  to  carry 
the  gas  down  to  a  depth  of  150  to  200  fathoms,  and  to 
maintain  sufficient  pressure  at  the  burners.  In  mines 
where  furnaces  are  used  for  ventilation  the  retorts  are 
sometimes  placed  over  the  furnace,  and  the  gas  is  purified 
and  stored  underground. 

•In  the  United  States  a  kind  of  gas  is  produced  for 
mining  and  other  purposes  by  forcing  common  air  through 
benzoline.  This  gas  is  slightly  heavier  than  air,  so  that 
no  difficulty  is  experienced  in  conveying  it  underground, 
as  is  sometimes  the  case  with  coal  gas.  The  first  cost  of 
the  apparatus  is  much  less  than  that  necessary  for  the 


VENTILATION   OP    UNDERGROUND   WORKINGS.         123 

production  of  coal  gas,  the  complete  arrangement  for 
100  lights  only  costing  from  £60  to  £100.  The  forcing 
apparatus  is  a  kind  of  clockwork,  which  is  wound  up 
each  morning  by  one  man  in  less  than  an  hour,  and  the 
light  is  said  to  be  quite  equal  to  coal  gas,  or  even  superior 
to  it.  The  cost  for  each  light  is  about  |d.  per  hour. 
This  would  be  too  costly  a  light  to  supply  to  each  pair 
of  men;  but  not  too  costly  for  the  lighting  of  shafts  and 
main  roads,  or  levels,  or  other  fixed  positions,  where  a 
constant  light  is  needed.  This  mode  of  gas  lighting  is 
now  to  be  seen  in  the  International  Exhibition  at  South 
Kensington  (July  1874).  It  seems  to  be  admirably 
adapted  for  mining  purposes. 


EXAMINATION   QUESTIONS. 


Ilia  numbers  within  "brackets  refer  to  the  paragraphs  in  whicJi  the 
material  for  answering  the  respective  questions  may  be  found. 


1.  What  branches  of  science  are  of  especial  value  to  miners?  [3-7]. 

2.  What  is  the  meaning  of  the  term  "crust"  of  the  earth?  [8]. 

3.  What  do  you  understand  by  the  terms  stratified  rock,  un- 
Btratified  rock,  and  metamorphic  rock?  [10,  11,  12], 

4.  What  is  "killas,"  and  where  is  it  found?  [13]. 

5.  What  are  the  leading  groups  or  "formations"  of  stratified, 
rocks?    Describe  the  chief  nuneral  contents  of  each  [13]. 

6.  How  do  the  rocks  called  "Elvan"  occur?    Illustrate  your 
answer  by  a  sketch  [15.] 

7.  What  is  the  general  influence  of  elvans  upon  mineral  veins 
or  lodes?  [15]. 

8.  What  do  you  understand  by  the  terms  mineral)  ore,  and 
rock?  [17,  18]. 

9.  Mention  six  metallic  minerals  or  ores,  and  state  the  propor- 
tions or  percentages  of  metal  they  contain  when  pure  ?  [19]. 

10.  What  are  the  most  common  non-metallic  minerals  or 
spars?  [20]. 

11.  Describe  six  different  kinds  of  rock  [21]. 

12.  Describe  the  usual  mode  of  occurrence  of  mineral  lodes  or 
rake-veins,  and  illustrate  your  remarks  by  sketches  [22], 

13.  What  do  you  understand  by  the  terms  pipe -vein,  flat, 
carbona,  and  stockwerke  [23-26]. 

14.  What  do  you  understand  by  the  terms  capel,  stickings,  or 
selvage?  [26]. 

15.  What  is  a  "horse"  of  ground?  [27]. 

16.  What  is  the  average  width  and  underlie  of  the  Cornish  tin 
and  copper  lodes?  [27]. 

17.  What  are  right-running  and  what  caunter  lodes?  [28]. 

18.  What  phenomena  are  observable  frequently  at  the  points 
of  intersection  of  right-running  lodes  by  caunters  and  cross- 
courses?  [28]. 

19.  Illustrate  by  a  sketch  the  position  of  the  hanging  wall  and 
foot-wall  of  a  lode. 

20.  What  is  the  mean  bearing  of  the  tin  and  copper  lodes, 
caunters,  and  cross-courses  in  Cornwall?  [28]. 

21.  What  are  the  indications  which  guide  the  miner  in  his 
search  for  minerals  in  untried  countries  ?  [29]. 

22.  What  is  the  gossan  which  frequently  occurs  on  the  backs 
of  lodes?    What  Jodes  have  frequently  no  gossan?    [30], 


12G  EXAMINATION   QUESTIONS. 

23.  Describe  the  process  of  costeaning  [34]. 

24.  State  what  you  know  of  heaves.     If  in  driving  due  east  on 
a  lode  a  cross-course  bearing  north-west  was  met  with,  and  the 
lode  was  not  found  on  driving  through  the  cross-course,  would 
you  be  more  likely  to  find  the  lode  by  driving  to  the  right  or  the 
left?  [36]. 

25.  Can  any  idea  of  the  extent  of  a  heave  be  formed  by  observ- 
ing the  size  of  the  cross-course  or  cross-vein  which  heaves  it? 
[37]. 

26.  What  is  the  difference  between  an  ordinary  heave  and  a 
"slide?"  [39]. 

27.  What  do  you  understand  by  the  terms  "dead  work"  and 
"productive  work?"  [40.] 

28.  What  is  an  adit  level  ?  Give  particulars  of  any  remarkable 
adits  of  which  you  have  heard,  or  with  which  you  may  be  ac- 
quainted [42]. 

29.  What   are   "winzes,"   and  with  what  object   are   they 
made?  [42]. 

30.  What  are  "shoots  of  ore  ?"    Illustrate  your  answer  by  a 
sketch  [42]. 

31.  What  are  the  ordinary  dimensions  of  shafts  in  metal  mines, 
and  why  are  shafts  in  hard  ground  usually  larger  than  in  soft 
ground?  [44]. 

32.  Compare  the  advantages  and  disadvantages  of   "down- 
right" and  "underlie"  shafts  [45]. 

33.  How  are  shafts  "secured"  in  tender  ground?    Show  by 
sketches  the  difference  between  different  modes  of  shaft  timber- 
ing [46,  47]. 

34.  What  are  the  sizes  of  ordinary  levels  in  metal  minee?  [48]. 

35.  How  much  run  or  fall  is  usually  given  to  a  level  in  which 
a  tram-road  is  laid?  [48]. 

36.  Show  by  sketches  the  various  modes  of  timbering  levels  [48]. 

37.  Why  is  the  "  cap-piece  "  in  timbering  a  level  usually  made 
shorter  than  the  "stretchers,"  and  why  are  the   "legs"  in- 
clined? [48]. 

38.  Compare  the  cost  of  "sinking"  and  "driving"  in  soft 
killas  or  clay  ground,  in  compact  killas  or  pick  and  gad  ground, 
and  in  fair  blasting  ground  [51]. 

39.  Calculate  the  cost  of  timbering  a  level,  in  moderately  soft 
ground,  7  feet  high,  3  feet  6  inches  in  the  cap,  and  4  feet  6  inches 
at  bottom  [52]. 

40.  Compare  the  advantages  and  disadvantages  of  the  different 
modes  of  "overhand"  and  "underhand"  stoping  [54]. 

41.  How  are  the  walls  of  the  lode  supported  after  the  mineral 
is  removed  [54]. 

42.  What  will  be  the  average  cost  of  stoping  fair  blasting 
ground  ?  [54]. 


EXAMINATION  QUESTIONS.  127 

43.  What  are  the  advantages  and  disadvantages  of  the  dif- 
ferent forms  of  "  tut  work  "  as  compared  with  "  tribute  work?" 
[55-57]. 

44.  What  are  the  directions  of  the  chief  "  faults  "  in  different 
mining  districts  ?  [60]. 

45.  State  the  advantages  of  trial  borings  in  bed  mining  [60]. 

46.  What  do  you  know  of  the  different  modes  of  executing  trial 
borings,  and  of  their  relative  cost  ?  [61,  62]. 

47.  What  considerations  should  guide  the  miner  in  determin- 
ing the  position  of  shafts  ?  [41,  44,  63]. 

48.  Describe  some  approved  modes  of  working  beds  of  iron  ore 
[63,  64]. 

49.  What  is  the  average  cost  of  "getting"  iron  ore  from  the 
"headings  "  and  "  pillars  "  respectively  of  a  bed  mine  ?    What 
minerals  are  found  in  beds  of  "  alluvial  "  gravel  ?  [69]. 

50.  Describe  some  approved  mode  of  working  beds  of  tin 
gravel  in  the  so-called  "alluvial"  mining  without  removing  the 
overburden  [65-68]. 

61.  How  would  you  work  a  bed  of  gravel  for  tin  or  gold  when 
the  overburden  is  only  a  few  fathoms  in  thickness  ?  [70]. 

52.  State  what  you  know  of  the  so-called  "  hydraulic  "  mining 
170]. 

53.  What  quantities  of  oxide  of  tin  per  ton  of  stuff  have  been 
found  sufficient  to  pay  cost  in  different  districts  and  under  dif- 
ferent circumstances  ?  [71]. 

54.  How  is  China  clay  worked  in  Cornwall  ?    How  much  stuff 
can  one  man  bring  down  in  a  day  of  eight  hours  under  favourable 
circumstances  when  aided  by  a  stream  of  water  ?  [72]. 

55.  What  is  the  usual  cost  of  removing  overburden  ?  [73]. 

56.  Describe  in  detail  the  process  of  boring  holes  for  blasting 
in  different  districts  [74]. 

57.  How  is  a  hole  charged  with  gunpowder  for  blasting  ?  [74]. 

58.  What  explosives  other  than  gunpowder  are  in  use  ?   What 
advantages  have  these  under  certain  circumstances  ?  [75,  76].  _ 

59.  Describe  three  forms  of  pick,  giving  sketches  and  stating 
weights  and  dimensions  [80]. 

60.  Describe  three  forms  of  hammers  used  by  miners,  giving 
sketches  and  stating  weights  and  dimensions  [81]. 

61.  Describe  the  Cornish  long-handled  shovel,  and  state  its 
size,  weight,  and  price  [82]. 

62.  What  are  the  relative  advantages  of   the   long-handled 
Cornish  shovel,  and  the  short-handled  shovel  used  in  the  North 
of  England  under  different  circumstances  ?  [82]. 

63.  Describe  the  different  forms  of  wedges  or  gads  used  in 
metal  mining,  giving  sketches  and  stating  weights  [83]. 

64.  Describe  the  ordinary  "borers"  used  in  metal  mining 
[84]. 


128  EXAMINATION   QUESTIONS. 

65.  Describe    the    "jumper,"    "tamping -bar,"  and  "swab- 
stick"  [84].  ' 

66.  What  are  the  tools  used  by  miners  in  preparing  timber  for 
shafts  and  levels  ?  [85]. 

67.  In  siuking  a  shaft  below  a  given  level,  how  should  the  men 
in  the  bottom  or  the  shaft  be  protected  from  the  fall  of  stones 
from  above  ?  [87 J. 

68.  What  are  "  striking  deals,"  and  what  is  their  use  ?  [88]. 

69.  Show  by  a  sketch  the  mode  of  dividing  an  engine-shaft  for 
pumping,  winding,  and  ladder-way  [88]. 

70.  What  is  the  usual  mode  of  constructing  ladders  for  use 
in  mines,  and  how  are  they  placed  in  the  shaft  ?  [89], 

71.  What  are  the  usual  lengths  of  ladders,  and  how  far  apart 
are  the  rungs  or  staves  placed  ?  [89]. 

72.  Describe  the  construction  of  "shaft  partings  "  and  ' ' sollars  " 
[89,  90]. 

73.  Describe  some  form  of  "  safety  catch."     What  are  the  ad- 
vantages and  disadvantages  of  such  contrivances  ?  [91]. 

74.  Describe  the  Cornish  man-engine  [93]. 

75.  Give  an  estimate  of  the  cost  of  supplying  a  man-engine  to 
a  depth  of  200  fathoms,  with  driving  engine  complete,  and  com- 
pare this  cost  with  the  amount  of  labour  saved  to  the  men  in 
climbing  from  great  depths  [94]. 

76.  What  are  the  usual  forms  and  weights  of  tram  rails,  and 
the  gauges  to  which  they  are  laid  ?    Illustrate  your  answer  by 
sketches  [97]. 

77.  Describe  the  wheel-barrow  used  in  the  Cornish  mines  [96]. 

78.  What  will  be  the  weight  of  a  tram-waggon  of  boiler  plate 
of  the  usual  construction,  42  inches  long,  30  inches  wide,  and 
18  to  20  inches  high  ?    How  much  iron  ore  will  such  a  waggon 
hold?  [97]. 

79.  Describe  in  detail  the  construction  of  a  "tackle,"  "wind- 
lass," or  "jack-roll."    What  is  its  cost  ?  [105]. 

80.  What  is  a  "kibble ?"     Compare  the  sizes  and  capacities  of 
winze-kibbles,  whim-kibbles,  and  engine -kibbles  [99]. 

81.  Describe  the  mode  of  preparing  a  shaft  for  running  a 
"skip  "[99]. 

82.  What  is  the  cost  of  a  double  skip  road  per  fathom  of 
length?  [99]. 

83.  Compare  the  cost  of  raising  mineral  from  shafts  of  various 
depths  by  means  of  (a)  a  tackle  worked  by  two  men;  (b)  a  one- 
horse  whirn  or  whipsey-derry;  (c)  a  two-horse  whim;  (d)  a  water- 
wheel;  (e)  a  steam  engine  [100]. 

84.  Compare  the  relative  advantages  and  disadvantages  under 
.different  conditions  of  (a)  kibbles;  (b)  skips;  (c)  cages  [101]. 

85.  Compare  the  relative  advantages  and  disadvantages  under 
different  conditions  of  (a)  chain;    (b)  hemp  rope;  (c)  iron  wive 
rope  (d);  steel  wke  rope  [102,  103]. 


EXAMINATION  QUESTIONS.  129 

88.  With  a  breaking  strain  of  8.  18,  and  40  tons  respectively, 
what  working  loads  may  be  adopted  for  wire  rope;  will  the  same 
ratio  between  working  load  and  breaking  strain  hold  good  in  the 
case  of  henip  ropes?  [104]. 

87.  Why  is  a  chain  less  suitable  for  drawing  stuff  from  a  deep 
than  a  shallow  mine?  [104]. 

88.  Describe  in  detail  the  mode  of  constructing  a  horse  whim; 
what  is  its  average  cost?  [106]. 

89.  Describe  the  construction    of   poppet  heads,   and  give 
sketches  in  illustration  of  your  answer.    What  will  be  the  cost  of 
poppet  heads  for  whim  drawing?  [107]. 

90.  Describe  any  methods  of  raising  mineral  by  water  power 
with  which  you  may  be  acquainted  [108,  109]. 

91.  What  is  the  cost  of  raising  mineral  by  the  water  balance 
in  North  Wales?    Under  what  conditions  is  this  mode  of  raising 
mineral  to  be  recommended?  [109]. 

92.  Compare  the  relative  advantages  of  the  Cornish  winding 
engine,  and  the  double  cylindered  horizontal  engine  [110,  111]. 

93.  Describe  with  a  sketch  the  common  suction  pump  [114]. 

94.  Make  a  sketch  of  a  common  "drawing  lift,"  showing  the 
situation  of  the  "clack"  and  "doorpiece." 

95.  Make  a  sketch  of  an  ordinary  "  plunger  lift,"  showing  the 
situation  of  the  "clacks"  [114]. 

96.  What  modifications  would  you  introduce  into  pit  work  in 
the  case  of  a  mine  containing  water  of  a  corrosive  nature?  [117]. 

97.  In  some  mines  the  men  are  In  the  habit  of  allowing  piles 
of  stuff  to  accumulate  in  the  levels;  what  are  the  objections  to 
this  practice? 

98.  Why  should  "levels"  be  driven  truly  level,  or  nearly 
so?  [116]. 

99.  Make  a  drawing  of  a  good  form  of  tackle,  windlass,  or 
jack-roll,  with  dimensions  marked  thereon. 

100.  State  howmuchwork  may  be  done  with  atackle  by  twomen. 

101.  Make  a  drawing  illustrating  the  working  of  a  drawing 
lift,  and  describe  the  several  parts;  why  is  a  drawing  lift  used 
while  sinking?  [114]. 

102.  Do  the  same  for  the  plunger  lift  [114]. 

103.  Make  a  sketch  with  dimensions  of  a  good  form  of  tram- 
waggon  or  tub  [72].      - 

104.  What  measures  may  be  taken  without  using  machinery 
for  improving  the  ventilation  of  a  mine?  [145-148]. 

105.  What  are  the  objections  to  "  over-stamping  "  of  ore?  [136]. 

106.  How  are  the  "pumps"  fixed  together  so  as  to  produce 
an  air  and  water-tight  joint?  [118]. 

107.  What  is  the  construction  of  a  main-rod,  and  how  are  the 
secondary  rods  attached  to  it?    Illustrate  your  answer  by  a 
sketch  [119]. 

18s  i 


130  EXAMINATION  QUESTIONS. 

108.  How  is  the  main-rod  secured  to  the  engine  beam  or 
bob?  [119]. 

109.  What  are  the  "  catch  pieces,"  and  what  is  their  use?  [119]. 

110.  When  the  weight  of  the  pump-rods  is  more  than  is  needed 
to  force  up  the  water  through  the  "plunger  lifts,"  how  is  the 
extra  weight  counterbalanced?    Show  by  a  sketch  the  construc- 
tion of  the  contrivance  adopted  [119]. 

111.  Ho'w  is  the  direction  of  the  pump-rods  changed  in  shafts 
with  varying  underlie?  [120], 

112.  What  is  the  "duty"  of  steam  engines?  [129]  • 

113.  Describe  the  variations  in  natural  ventilation  at  different 
seasons  of  the  year  [119]. 

114.  Why  is  it  not  a  proof  of  good  ventilation  in  a  mine  to 
have  a  very  rapid  current  of  air  in  a  small  place  ?  [115]. 

115.  Describe  the  water  blast  or  trompe,  and  give  a  sketch 
showing  its  mode  of  action  [117]. ' 


GLOSSARY. 


(See  also  Index  for  many  technical  names.) 


Account -house,  the  house  in 
which  the  captains  or  agents 
of  a  mine  keep  the  accounts 
and  superintend  the  work- 
ings. 

Adit,  the  water  level  of  a  mine. 

Adlings,  earnings. 

Adventurers,  the  owners  of  a 
mine,  or  the  individuals  who 
together  form  the  mining 
company. 

After-damp,  the  poisonous  gas 
which  results  from  an  explo- 
sion of  foul  gas  or  fire-damp 
in  a  coal  mine.  It  consists 
chiefly  of  the  gas  called  car- 
bonic acid,  mingled  with 
much  steam.  It  is  often 
called  choke-damp,  because 
it  suffocates  many  of  the  men 
who  may  have  been  uninjured 
by  the  actual  explosion. 

Agents,  the  managers  or  over- 
seers of  a  mine. 

Air-machine,  an  apparatus  for 
forcing  fresh  air  into,  or 
withdrawing  foul  air  from,  a 
mine.  A  ventilating  machine. 

Air-pipes,  pipes  for  conveying 
fresh  air  into  the  levels. 

Aitch -piece,  that  part  of  a 
plunger  lift  in  which  the 
valves  or  clacks  are  fixed. 

Alabaster,  a  kind  of  gypsum. 

Alloys,  combinations  of  two  or 
more  metals  with  each  other 
are  so  called.  Thus  brass  is 
an  alloy  of  zinc  and  copper, 
and  bronze  of  tin  and  cop- 
per. 


Amalgam,  an  alloy  of  which 
mercury  or  quicksilver  is  one 
of  the  ingredients. 

Amalgamation,  the  mode  of 
separating  gold  or  silver  from 
their  ores  by  means  of  mer- 
cury. 

Analysis,  the  act  of  determining 
the  composition  of  an  un- 
known substance.  Qualitative 
analysis  determines  the  na- 
ture, and  quantitative  analysis 
the  proportions  of  the  various 
substances. 

Ancients.    See  "Old  Men." 

Anhydrous,  minerals  and  other 
substances  which  are  free  from 
or  do  not  contain  water  are 
said  to  be  anhydrous. 

Aqueous,  watery. 

Arch,  a  piece  of  ground  left  un- 
worked  near  a  shaft  or  in  a 
stope. 

Arenaceous,  containing  sand,  or 
consisting  principally  of  sand. 
Thus,  sandstones  are  said  to 
be  arenaceous  rocks. 

Argentiferous,  containing  silver. 
Thus,  those  kinds  of  galena 
which  contain  a  considerable 
proportion  of  silver  are  said 
to  be  argentiferous. 

Argillaceous,  containing  clay,  or 
of  a  clayey  nature.  Thus, 
clays,  shales,  and  clay-slates 
are  said  to  be  argillaceous 
rocks. 

Assaying,  the  art  of  determining 
the  proportion  of  any  given 
substance  in  an  ore  or  mix- 


132 


GLOSSARY. 


ture.  It  differs  from  an  an- 
alysis in  only  determining 
certain  stated  substances. 

Attle,  waste  or  rubbish.  The 
waste  or  rubbish  of  a  mine  is 
called  "attle"  or  "deads." 

Auriferous,  containing  gold.  Py- 
rites, or  sands  containing  gold, 
are  called  auriferous  pyrites, 
or  auriferous  sands.  - 

Back,  a  slippery  or  clayey  joint 
or  division  in  a  bed  of  coal  or 
hard  rock.  Sometimes  called 
a  "face." 

Back  of  a  lode,  the  upper  part 
or  outcrop  of  a  lode  at  the 
surface  of  the  ground ;  or  that 
part  which  is  "above"  the 
men  in  any  level. 

Back-shift,  the  second  set  of 
miners  working  in  any  spot 
each  day. 

Bal,  a  common  Cornish  term  for 
a  mine.  It  applies  rather  to 
the  surface  than  the  under- 
ground workings. 

Balk.     See  "Nip." 

Balland,  a  Derbyshire  term  for 
lead  ore  in  a  finely  divided 
state. 

Bank  or  Benk,  the  surface  of  any 
mine,  called  "  grass "  by 
Cornish  miners.  Also  the 
place  from  which  the  miners 
are  turning  out  coal. 

Banksman,  the  man  who  re- 
ceives the  ore  at  the  top  of 
the  pit. 

Bargain,  an  agreement  between 
any  party  of  miners  and  the 
managers  of  a  mine  to  work 
any  stated  point  at  a  given  rate. 

Bar  Master,  an  officer  who 
superintends  the  lead  mines 
of  Derbyshire. 

Barrowman.    See  "Putter," 


Basaltic,  consisting  of  or  resem- 
bling basalt. 

Bass  or  Batt.    See  "Bind."' 

Basset  edge,  that  edge  of  a  bed 
which  appears  at  the  surface. 
See  "Cropping  Out." 

Bast,  a  miner's  supply  of  food 
for  eating  during  work  hours, 
called  also  "crib." 

Beans,  small  coals. 

Bearer  or  Biard,  a  large  piece  of 
timber  used  to  support  the 
engine  and  pumps  or  other 
machinery  in  or  over  the 
engine  shaft.  , 

Beche  or  Bitch,  a  boring  tool. 

Bender,  a  piece  of  iron  attached 
to  barrels,  etc.,  to  which  the 
pit-rope  is  affixed. 

Bind,  a  quarryman's  or  collier's 
term  for  a  dark  slaty  kind  of 
hardened  clay. 

Binghole,  a  hole  through  which 
ore  is  thrown.  A  Derbyshire 
term. 

Bit,  the  working  end  or  steel 
tip  of  a  borer,  or  the  borer 
itself. 

Black  Jack,  See  "Blende." 

Black  Tin,  tin  ore  ready  for 
smelting. 

Blasting,  breaking  away  masses 
of  rock  by  means  of  gun- 
powder or  other  explosives. 

Blasting  Cone,  a  conical  plug  of 
wood  or  metal,  sometimes  in- 
troduced into  the  upper  part 
of  a  hole  for  blasting^  above 
the  powder,  to  serve  instead 
of  tamping. 

Blasting  Needle,  an  instrument 
used  in  blasting. 

Blende,  an  ore  of  zinc. 

Blue  Elvan,  a  Cornish  term  for 
greenstone. 

Blue  John,  the  Derbyshire  name 
for  fluor  spar. 


GLOSSARY. 


133 


Bob,  the  beam  of  the  engine. 

Bonnet,  the  covering  to  the 
safety  cage,  to  protect  men 
from  injury  from  falling 
stones,  etc. 

Bord,  Board,  Bord-gate,  or  Brow, 
any  gallery  in  a  mine  which 
is  driven  across  the  "face" 
of  the  coal  or  ore. 

Borer  or  Borier,  the  long  tool  or 
chisel  used  for  boring  holes 
for  blasting  in  mines. 

Bottoms,  the  lowest  workings 
in  a  mine  or  in  a  level. 

Boulders,  large  masses  of  rock 
of  a  somewhat  rounded  form. 

Bowze,  lead  ore  as  cut  from  the 
lode. 

Brakesman,  the  man  in  charge 
of  a  winding  engine. 

Brances,  pyrites  in  coal. 

Branches^  small  veins  of  ore  in 
connection  with  a  main  or 
principal  lode. 

Brattice,  a  temporary  partition 
made  for  the  purpose  of  di- 
recting the  currents  of  air  in 
a  mine. 

Breccia,  a  rock  made  up  of  an- 
gular fragments  of  other 
rocks,  "When  made  of  rounded 
pebbles  it  is  called  a  con- 
glomerate. 

Brittle,  anything  easily  broken. 
In  mineralogy  the  term  is 
used  in  distinction  to  "tough." 
Thus  schorl  is  brittle  and 
hornblende  is  tough. 

Brood,  the  heavier  kinds  of 
waste  in  tin  and  copper  ores. 

Bryle,  the  traces  of  the  presence 
of  a  lode  at  surface. 

Bucket,  the  piston  of  a  lifting 
pump. 

Bucking,  a  method  of  breaking 
the  poorer  sorts  of  copper  and 
lead  ores  into  small  fragments 


by  means  of  flat  irons,  called 
bucking  irons.  It  is  now 
nearly  superseded  by  crush- 
ing machinery. 

Bucking  Iron,  the  iron  with 
which  bucking  is  done. 

Bucking  Plate,  an  iron  plate  on 
which  the  ore  is  bucked. 

Bucklers.     See  "Tacklers." 

Buddie,  a  contrivance  for  wash- 
ing impurities  from  stamped 
or  finely -ground  ores. 

Buddling,  separating  ores  from 
waste  by  means  of  the  buddle. 

Bunch,  a  rich  deposit  of  ore  of 
small  extent. 

Burden,  the  top  or  waste  in 
stream-works,  etc. ,  which  lies 
over  the  layer  of  stream-tin 
or  other  material  sought  for. 
The  same  word,  or  "over- 
burden," is  used  by  quarry- 
men  with  reference  to  the 
waste  which  overlies  the  good 
stone  in  a  quarry. 

Burning,  the  operation  of  roast- 
ing an  ore  for  the  purpose  of 
driving  off  sulphur,  arsenic, 
moisture,  etc.  It  is  the  same 
as  calcining. 

Burning-House,  the  place  where 
the  "burning"  is  conducted. 

Burrow,  a  heap.  The  heaps  of 
attle,  deads,  or  waste  thrown 
out  from  a  mine  are  so  called. 

Butty,  a  person  who  contracts  to 
raise  ore  from  any  given  point 
in  a  mine  at  a  certain  fixed 
rate  per  ton,  making  his  own 
arrangements  with  the  miners. 

Cage,    a   machine  for   raising 

miners  or  ore. 
Cage,  the  barrel  on  which  the 

rope  is  wound  in  a  whim. 
Calcination.     See  "Burning." 
Cann,  Kann;  or  Hand,  iluor  spar. 


134 


GLOSSARY^ 


Capel,  a  very  hard  substance 
which  often  forms  the  sides  of 
tin  lodes.  It  frequently  con- 
tains small  quantities  of  tin 
ore. 

Carfoona,  an  irregular  deposit  of 
ore  found  in  connection  with 
some  tin  lodes  in  the  west  of 
Cornwall. 

Casing,  a  wooden  partition  sepa- 
rating the  footway  from  the 
other  portions  of  a  shaft. 

Gaunter,  a  mineral  lode  whose 
direction  crosses  that  of  the 
main  lodes  of  a  district. 

Chert,  a  hard  flinty  substance 
found  in  connection  with 
some  limestone,  and  valuable 
for  road-making. 

China-clay,  a  white  and  pure 
kind  of  clay  used  in  the 
manufacture  of  china.  It  is 
abundant  in  Cornwall  and 
Devonshire. 

China-stone,  a  white  decom- 
posed variety  of  granite  con- 
taining little  or  no  mica, 
which  is  much  used  for  the 
finer  kinds  of  pottery. 

Chlorite,  a  soft  green  mineral 
which  often  accompanies  tin 
and  other  ores. 

Clack,  the  valve  of  a  pump. 

Claggy,  sticky. 

Clay  Iron,  an  instrument  of  iron 
used  for  lining  bore  -  holes 
with  clay  to  prevent  the  gun- 
powder from  becoming  wet. 

Cleat.     See  "Joints." 

Cleavage,  the  property  which 
many  minerals  and  rocks 
possess  of  splitting  more  easily 
and  perfectly  in  some  direc- 
tions than  in  others.  In  rocks 
the  cleavage,  when  present, 
is  usually  much  more  distinct 
and  perfect  than  the  bedding. 


Gleet,  a  wedge ;  also  a  strength- 
ening piece  of  wood. 

Cockle,  the  Cornish  name  for 
schorl  or  black  Tourmaline. 

Coffer,  Cofer,  or  Cover,  the  box 
into  which  ore  falls  in  order 
to  be  pulverised  by  the  stamp- 
ing mill. 

Coffins,  a  series  of  long  narrow 
workings,  each  one  being 
about  6  feet  deeper  than  the 
one  next  to  it.  This  mode  of 
working  was  formerly  adopted 
in  place  of  sinking  shafts. 

Conglomerate,  a  rock  made  up 
of  rounded  pebbles. 

Coper,  one  who  contracts  to 
raise  lead  ore  at  a  fixed  rate. 

Copper  Pyrites.  See  "Chalco- 
pyrite." 

Core,  the  space  of  time  during 
which  miners  remain  under- 
ground at  their  work.  In 
Cornwall  this  is  usually  eight 
hours.  In  many  mines  the 
men  are  divided  into  three 
parties,  each  working  eight 
hours,  so  that  the  work  is 
carried  on  uninterruptedly. 

Corve  or  Corf,  a  square  frame  of 
wood  for  carrying  or  sliding 
coal  or  ore  upon  at  the  bottom 
of  the  mine .  Sometimes  called 
a  "dan." 

Costeaning,  searching  for  ore  by 
sinking  shallow  pits  in  likely 
places,  and  driving  short  gal- 
leries, or  cross-cuts,  from  one 
to  another. 

Count  House.  See  "Account- 
house." 

Country,  the  rocks  in  which  a 
lode  may  occur  are  in  Corn- 
wall called  the  "country." 

Course,  a  vein.  Thus  men  speak 
of  a  "course  of  ore,"  an  elvau 
"course,"  etc. 


GLOSSARY. 


135 


Crab,  a  machine  used  for  rais- 
ing weights. 

Crane,  a  machine  for  raising 
heavy  weights. 

Craze,  coarse  fragments  of  im- 
pure ore  separated  in  a  late 
stage  of  tin-dressing. 

Creep,  the  raising  of  the  floor 
of  a  bed  mine  after  the  ore 
is  removed  from  the  weight 
of  the  rocks  above  forcing  the 
pillars  left  for  support  down 
into  those  below. 

Crib  or  Curb,  a  frame  of  wood 
or  iron  forming  the  founda- 
tion of  the  lining  or  tubbing 
of  a  shaft. 

Crib,  a  miner's  luncheon. 

Cropping  out,  the  appearance 
of  a  lode  or  bed  at  the  sur- 
face of  the  earth. 

Crop-tin,  the  chief  portion  of 
the  tin  ore,  which  is  sepa- 
rated from  its  waste  in  the 
principal  dressing  operations. 
The  finer  portions,  which  are 
carried  away  by  the  water, 
are  called  "slime ; "  and  that 
which  is  too  coarse  is  called 
"rows"  or  "roughs." 

Cross-course,  any  vein  consist- 
ing principally  of  quartz, 
whose  direction  is  across  that 
of  the  lodes  in  a  given  dis- 
trict. 

Cross-cut,  in  metal  mining,  a 
gallery  or  level  driven  across 
the  usual  direction  of  the 
lodes,  usually  for  the  purpose 
of  searching  for  a  new  lode  or 
of  connecting  two  known 
lodes. 

Crowbar,  a  strong  bar  of  iron 
much  used  as  a  lever  in  quar- 
ries and  other  places  for  mov- 
ing heavy  masses, 

Colni,  hard  coal. 


Cupreous,  containing  copper. 
Cut,  to  intersect  a  lode  is  called 

cutting  the  lode. 
Cutter,  see  "joints." 

Damp,  a  miner's  term  for  foul 
air.  See  "Fire-damp"  and 
"After-damp." 

Dan,  see  "Corve." 

Dead  Ground,  a  portion  of  the 
lode  containing  little  or  no  ore. 

Deads,  see  "Attle." 

Derrick,  a  pulley  for  raising  a 
kibble  from  small  depths  in 
which  the  horse  simply  walks 
forward. 

Desuing,  working  away  the 
country  at  the  side  of  a  lode 
so  as  to  break  ore  easier.  It 
is  done  when  the  lode  is 
harder  than  the  country. 

Dial,  a  kind  of  compass  used  for 
taking  bearings  underground. 

Dialling,  the  art  of  surveying 
by  means  of  the  instrument 
called  the  miner's  dial. 

Dip,  the  amount  of  slope  of  a 
bed  or  vein  measured  from  a 
horizontal  line.  See  "Under- 
lie." 

Direction,  the  point  of  the  com- 
pass towards  which  any  vein 
or  lode  tends  is  its  direction. 
The  same  as  bearing. 

Disintegrate,  to  break  up  from 
the  effect  of  decomposition. 

Disseminated,  sown  or  sprinkled. 
Minerals  which  occur  in  small 
particles  throughout  the  mass 
of  a  rock  are  said  to  be  disse- 
minated. Thus  tin  ore  is  often 
found  disseminated  in  granite. 

Dole,  a  division,  as  one-sixth, 
one-eighth,  and  the  like,  of  a 
parcel  of  ore. 

Downcast,  the  downward  cur- 
rent of  air  in  a  mine. 


136: 


GLOSSARY. 


Dredge,  very  fine  matter  held 
in  suspension  in  water. 

Dresser,  the  person'  who  under- 
takes the  dressing  of  ores. 

Dressing  of  Ores,  the  act  of 
separating  ores  from  waste 
matter  and  preparing  them 
for  sale. 

Drift,  any  working  underground 
which  is  horizontal  or  nearly 
horizontal. 

Driving,  working  horizontally, 
either  along  or  across  the 
course  of  the  lode. 

Dropper,  a  branch  or  string 
which  leaves  the  main  lode 
on  the  foqtwall  side. 

Drum,  a  kind  of  cage  upon 
which  chains  or  wire  ropes 
are  wound. 

Dry,  a  place  fitted  with  warm- 
ing apparatus  for  drying  the 
miners'  underground  clothes. 

Dues,  the  portion  of  the  pro- 
duce of  a  mine  which  is  paid 
to  the  land-owner  or  lord  of 
a  mine  in  lieu  of  rent. 

Duty  of  Steam  Engines,  the 
amount  of  work  done  by  any 
engine  by  the  consumption  of 
1  cwt.  of  coal. 

Dyke,  a  course  or  vein  of 
igneous  rock;  a  fault. 

El  van,  The  Cornish  name  for 
veins  or  courses  of  a  kind  of 
porphyry  which  sometimes 
extends  through  the  country 
in  the  manner  of  a  lode  for 
many  miles. 

End,  the  extreme  point  of  any 
level,  at  which  the  men  must 
work  in  extending  it  further. 

Engine  Shaft,  the  shaft  by  which 
the  drainage  water  of  the 
mine  is  raised  up  to  the  adit 
or  surface. 


Face,  see  "joint." 

Fathom,  6  feet.  In  metal  mines 
all  distances  are  reckoned  in 
fathoms. 

Fault,  a  disturbance  of  the 
strata,  as  shown  in  figs.  22, 
23.  When  the  displacement 
is  horizontal,  it  is  usually 
called  a  heave  by  miners  ;  if 
upwards,  a  lea})  or  upthrow; 
if  downwards,  a  slide  or  down- 
throw. 

Feather,  an  instrument  used  in 
wedging  off  masses  of  rocks. 
See  "  Plug  and  Feather." 

Feeder,  a  branch,  when  it  falls 
into  the  lode  on  the  hanging 
wall  side. 

Feign,  the  refuse  washed  from 
lead  ore  or  coal. 

Felspar,  a  mineral  harder  than 
calcite  and  softer  than  quartz,, 
which  breaks  readily  into 
fragments,  having  smooth 
sides  at  right  angles  to  each 
other.  It  forms  a  consider- 
able proportion  of  all  granites 
and  some  other  rocks. 

Ferruginous,  containing  iron. 

Filler,  the  man  who  fills  the 
kibble,  or  skip,  with  ore  at 
the  bottom  of  a  mine. 

Fissure,  a  crack.  Most  geolo- 
gists consider  that  lodes  are 
simply  fissures,  originally 
formed  by  earthquakes  or 
other  causes,  but  now  more 
or  less  completely  filled  with 
ores  and  veinstones. 

Flat  rods,  pump  rods  arranged 
to  work  horizontally  or  nearly 
so.  It  sometimes  happens 
that  an  engine  placed  over 
one  shaft  of  a  mine  is  re- 
quired to  work  the  pumps 
which  extend  down  another 
shaft  at  a  considerable  dis- 


GLOSSARY. 


137 


tance.  In  such  cases  the  con- 
nection is  made  by  means  of 
horizontal  pump -rods  or  "flat 
rods,"  running  upon  rollers 
to  lessen  friction. 

Flint,  a  variety  of  the  mineral 
quartz,  which  is  abundant  in 
chalk  rocks. 

Flookan  or  Flucan,  a  cross -vein 
which  is  filled  with  clayey 
matter.  Flookans  which  run 
parallel  with  the  lode  are 
sometimes  called  "course- 
flookans." 

Flux,  anything  added  to  an  ore 
so  as  to  render  it  more  readily 
fusible. 

Foot-wall.  See  "Walls  of  a 
Lode." 

Footway,  the  series  of  ladders 
and  sollars  by  which  men 
enter  or  leave  a  mine.  They 
are  sometimes  called  "way- 
gates"  or  "climbing  shafts" 
in  the  North  of  England. 

Fork,  in  Cornwall,  the  bottom 
of  the  sump,  which  see. 

Fork,  in  Derbyshire,  a  piece  of 
wood  used  to  keep  up  the  side 
of  an  excavation  in  soft 
ground. 

Founder-shaft,  the  first  shaft 
sunk  in  a  mine. 

Frame,  an  inclined  board  over 
which  a  gentle  stream  of 
water  is  made  to  flow,  for 
the  purpose  of  washing  away 
the  waste  from  small  por- 
tions of  ore  which  are 
placed  upon  it  from  time  to 
time. 

Freestone,  any  kind  of  compact 
stone  which  may  be  worked 
freely.  In  some  cases  sand- 
stones are  called  freestones, 
but  more  properly  the  name 
should  be  restricted  to  such 


soft    stones    as    Bath-stone, 

Painswick-stone,  etc. 
Friable,  anything  that  may  be 

easily  reduced  to  powder. 
Fuse,    a  kind    of    combustible 

cord  used  for  firing  powder 

in  blasting. 
Fuse,      to    melt.      Substances 

which  may  be  readily  melted 

are  said  to  be  fusible. 

Gad,  a  kind  of  wedge  used  in 
breaking  down  small  masses 
of  rock  in  mining. 

Galena,  the  most  common  ore 
of  lead. 

Gallery,  a  level  of  a  mine. 

Gangue,  the  valueless  material, 
or  "  veinstuff,"  in  which  the 
ores  of  metals  occur,  or  with 
which  they  are  often  mixed. 

Gate,  a  road  or  way  under- 
ground. 

Gin,  a  machine  for  raising  coal 
or  ore  from  a  mine.  A  whim. 

Girdle,  a  thin  layer  of  stone. 
Newcastle  term. 

Gneiss,  a  foliated  rock  composed 
of  quartz,  felspar,  and  mica. 
It  differs  from  granite  in 
these  minerals  occurring  in 
distinct  layers. 

Goaf  or  Gob,  the  old  deserted 
workings  of  a  mine,  often 
filled  up  with  rubbish.  In 
coal  mines  the  goaf  often 
contains  a  dangerous  accumu- 
lation of  gas. 

Gofien,  a  long  and  narrow  sur- 
face-working, perhaps  con- 
nected with  coffin  and  goaf, 
which  see. 

Gossan,  the  upper  decomposed 
portion  of  a  lode.  It  usually 
consists  of  a  mixture  of 
cellular  quartz  and  oxide  of 
iron,  and  often  extends  to 


138 


GLOSSARY. 


great  depths  in  copper  lodes. 
Also  a  kind  of  fault. 

Grain  Tin,  the  purest  kind  of 
metallic  tin. 

Granite,  a  crystalline  rock  com- 
posed of  quartz,  felspar,  and 
mica. 

Grass,  the  surface  of  a  metal 
mine.  Thus  miners  are  said  to 
come  "to  grass,"  when  they 
come  up  from  underground. 

Grate,  an  iron  plate  punched 
full  of  small  holes  through 
which  the  stamped  ore  passes 
from  the  coffer  to  the  dress- 
ing apparatus. 

Gravel,  small  waterworn  stones. 

Grey  Ore,  a  very  valuable  ore 
of  copper. 

Growan,  a  kind  of  coarse  sand 
produced  by  the  decomposi- 
tion of  granite  rocks.  Lumps 
of  granite  are  sometimes 
called  hard  growan. 

Guides,  a  local  name  for  certain 
cross  veins  in  the  west  of 
Cornwall. 

Gunnies,  abandoned  levels  or 
workings. 

Hack,  a  large  pick  used  for 
working  stone. 

Hade,  Hadeslope,  the  underlie 
or  inclination  of  a  lode. 

Halvans,  the  refuse  heaps  of 
mines,  which  still  contain  a 
small  portion  of  ore,  the  resi- 
due of  the  dressing  processes. 

Hanging-walL  See  "  Walls  of 
a  Lode." 

Hauling,  raising  ore  or  waste 
out  of  the  mine. 

Header,  see  "Joints." 

Heading,  a  small  gallery  driven 
in  advance  of  a  gate  road,  or 
for  any  temporary  purpose. 

Hematite,    red   hematite    and 


brown  hematite  are  valuable 
ores  of  iron. 

Hitch,  a  small  fault  which  does 
not  exceed  the  height  of  the 
bed  or  seam.  See  "  Fault." 

Hole,  to  hole  is  to  make  a  com- 
munication from  one  part  of 
a  mine  to  another.  Thus  a 
level  is  sometimes  driven  at 
the  same  time  from  two 
shafts  so  as  to  meet  or  hole 
a  point  between  the  two. 

Homogenous,  of  equal  composi- 
tion throughout.  Applied  to 
minerals. 

Horse,  any  piece  of  "country" 
included  within  a  wide  lode ; 
or  two  branches  of  a  lode  is 
called  by  metal  miners  a 
"  horse"  or  "  horse  of 
ground." 

Huel  or  Wheal,  the  Cornish 
name  for  a  mine. 

Hushing,  the  forcible  washing 
away  of  the  surface  soil  and 
sub-soil  on  a  hill  side,  by  a 
stream  of  water,  for  the  pur- 
pose of  laying  bare  the  mine- 
ral deposits.  It  is  adopted 
where  water  is  abundant  in- 
stead of  costeaning. 

Hydrous  or  Hydrated,  contain- 
ing water. 

Indicator,  an  instrument  for 
showing  the  position  of  the 
cage  or  skip  in  the  shaft. 

Indurated,  hardened. 

Infusible,  anything  which  can- 
not be  "  fused"  or  melted. 

Irestone  or  Ironstone,  a  Cornish 
term  for  greenstone,  given  on 
account  of  its  extreme  tough- 


Jack,  a  miner's  term  for  ziiio 
blende, 


GLOSSARY. 


139 


Jigging,  a  method  of  dressing 
poor  copper  and  lead  ores  by 
shaking  them  with  a  peculiar 
motion  in  a  kind  of  sieve 
which  is  made  to  move  up 
and  down  in  water. 

Joints,  natural  divisions  in 
masses  of  rock.  They  are 
variously  called  backs,  cut- 
ters, faces,  cleats  ends,  etc., 
according  to  their  relative 
positions,  the  locality,  and 
the  material  in  which  they 
occur. 

Judge,  a  staff  used  for  under- 
ground measurements. 

Jumper,  a  tool  used  in  quarries 
for  the  purpose  of  boring 
holes  for  blasting. 

Junction,  the  point  at  which 
two  veins  meet. 

Kann  or  Cann,  a  Cornish  miner's 

term  for  fluor  spar. 
Keeper,  an  overlooker. 
Keel,  a  large  boat  used  for  car- 
rying ore. 
Kevil,  a  sparry  substance  found 

in  the  Derbyshire  lead  veins, 

composed  of  calcite,  fluor,  or 

barytes. 
Kibble,   a  kind  of  iron  bucket 

used  in  many  metal  mines 

for  raising  ores. 
Kieve,  a  large  tub  of  wood  or 

iron  used  for  tozing  tin  ore 

before  selling. 
Killas,  a  Cornish  miner's  term 

for  all  kinds  of  slaty  rocks. 
Kit,  a  wooden  vessel. 
Knots,  small  particles  of  ore. 

Lander,  the  man  who  receives 

the  loaded  kibble  or  skip  at 

the  mouth  of  the  shaft. 

Laths.     See  '  <  Sets  and  Laths. " 

Launder,  a  gutter  of  wood  or 

metal    used    for    conveying 


small  streams  of  water  from 
place  to  place. 

Leader,  a  branch  of  ore  which 
if  followed  up  often  leads  to 
the  main  lode  with  which  it 
is  connected. 

Leadings,  small  sparry  veins  in 
the  rock.  A  Derbyshire  term. 

Leap.    See  "Fault." 

Leat,  a  water-course. 

Leavings,  waste  heaps  resulting 
from  the  dressing  of  ores. 

Levels,   galleries   driven   along 

_  the  lode,  in  Cornwall  usually 
at  depths  of  ten  fathoms  be- 
low each  other. 

Lewis,  an  instrument  of  iron 
used  for  raising  heavy  blocks 
of  stone. 

Lifters,  the  upright  beams  to 
which  the  heavy  stamp-heads 
are  attached  for  stamping 
ores. 

Limestone,  any  stone  consisting 
chiefly  of  carbonate  of  linie. 

Limp,  an  instrument  of  iron 
used  for  striking  the  refuse 
from  the  sieve  in  washing 
ores. 

Loch,  a  cavity  in  a  vein,  a  vugh. 
Derbyshire  term. 

Lode,  a  vein  of  any  metallic 
ore. 

Lord,  the  owner  of  the  land  in 
which  a  mine  is  situated  is 
called  the  "lord."  He  re- 
ceives generally  a  portion  of 
the  produce  of  the  mine,  in 
lieu  of  rent.  This  is  called 
the  "lord's  due."  It  is  fre- 
quently one-fifteenth  of  the 
produce  of  the  mine  in  Corn- 
wall. 

Mallet,  the  hammer  used  in 
striking  or  "beating"  the 
borer. 


140 


GLOSSARY, 


Man-engine,  a  machine  used  for 
raising  and  lowering  miners. 

Material  Man,  the  man  who  has 
charge  of  and  deals  out  the 
materials. 

Matrix,  the  substance  in  which 
any  portion  of  ore  occurs  em- 
bedded. 

Mattock.    See  "  Pick." 

Maul,  a  large  hammer  or  mallet. 

Mear,  32  yards  of  ground  meas- 
ured on  the  vein. 

Metalliferous,  containing  or 
yielding  metal  or  ore. 

Metallurgy,  the  art  of  extract- 
ing metals  from  their  ores. 

Micaceous,  containing  mica,  or 
occurring  in  thin  scales  like 
mica. 

Mineralised,  containing  particles 
of  some  "metallic"  mineral. 

Mock  Lead,  blende. 

Moorstone,  loose  masses  of 
granite  which  are  found  lying 
upon  the  moors  in  Cornwall. 

Mundic,  the  Cornish  and  Devon- 
shire term  for  iron  pyrites. 

Needle,  a  piece  of  stout  iron  wire 
used  to  make  a  hole  through 
the  tamping  of  a  hole  down 
to  the  gunpowder,  to  serve  as 
a  touch  hole.  It  is  called  a 
pricker  in  many  places. 

Nip,  a  sudden  thinning  of  a 
seam  of  coal  or  ore. 

Noger,  a  juniper,  borer,  or  drill. 

Nogs,  square  blocks  of  wood 
which  are  piled  one  upon 
another  to  support  the  roof  of 
a  coal  mine. 

Nuts,  small  coal. 

Ochre,  earthy  ores  of  iron  are 
called  ochres.  They  are  gene- 
rally red,  yellow,  or  brown. 

Old    Men,     the    persons    who 


worked  a  mine  at  any  former 
period  of  which  no  record 
remains. 

Old  Men's  Workings,  workings 
made  by  the  "old  men," 
sometimes  themselves  called 
old  men. 

Open  Cut,  an  open  cutting. 

Opens,  large  caverns. 

Ore,  any  natural  substance 
which  is  worked  for  the  metal 
it  contains. 

Outcrop.     See  "  Cropping  out." 

Overburden.     See  "  Burden. " 

Overman,  an  overlooker. 

Owner's  Account  Men,  men  paid 
at  a  fixed  rate  per  day. 

Oxide,  any  element  which  com- 
bined with  the  gas  oxygen 
forms  an  oxide. 

Packing.    See  "Tozing." 

Pair  or  Pare,  a  party  of  miner3 
who  agree  to  work  in  part- 
nership together.  A  pair  of 
men  usually  consists  of  more 
than  two  and  often  of  ten  or 

"  twelve  men. 

Parcel,  a  heap  of  ore  dressed 
and  ready  for  sale. 

Pass,  an  opening  left  for  letting 
down  ore  and  deads  to  any 
level. 

Peach,  the  Cornish  miners'  term 
for  chlorite. 

Pick  or  Pike,  slitter,  mattock, 
pike-hake. 

Pillar,  an  upright  piece  of  a  lode 
left  to  support  its  walls. 

Pipe-vein,  a  vein  of  ore  which 
is  bounded  above  and  below, 
as  well  as  on  both  sides,  by 
the  "country." 

Pit,  a  shaft. 

Pitch,  limit  of  the  ground  set 
to  tributers  or  tut-work 
men. 


GLOSSARY. 


141 


Pitman,  one  who  works  in  a 
shaft. 

Pitman,  one  who  has  to  look 
after  the  pumps  and  drainage 
of  a  mine.  In  Derbyshire, 
any  underground  worker. 

Pitwork,  the  pumps  and  other 
appliances  in  the  shaft. 

Plug  and  Feather,  instruments 
used  in  wedging  off  small 
masses  of  rock. 

Plumb,  soft. 

Plumb,  perpendicular  or  up- 
right. 

Plump,  a  Cornish  term  for  a  well. 

Plutonic  rocks,  such  rocks  as 
are  belived  to  have  been 
formed  deep  down  in  the 
earth.  Granite  and  porphyry 
or  el  van  are  Plutonic  rocks. 

Pocket.     See  "Bunch." 

Podar,  anything  that  is  brittle 
or  worthless.  The  term  is 
now  applied  to  mundic,  but 
yellow  ore  was  formerly  called 
podar  when  occurring  in  tin 
ores,  as  it  reduced  the  value 
of  the  tin. 

Point  of  Horse,  the  point  at 
which  a  lode  divides  into  two. 

Poll,  the  "head,"  "pane,"  or 
striking  part  of  a  miner's 
hammer  or  of  a  poll-pick. 

Poll-pick,  a  miner's  pick,  having 
one  end  sharp,  and  the  other 
formed  into  a  hammer. 

Porous,  containing  minute  pores 
or  holes. 

Porphyry,  any  rock  in  which 
distinct  crystals  of  any  kind 
are  embedded  in  a  non-crys- 
tallised mass.  The  elvans  of 
Cornwall  are  porphyries. 

Prian  or  Pryan,  a  soft  clayey 
substance  found  in  lodes. 

Pricker,  an  instrument  employed 
for  making  a  communication 


through  the  tamping  to  the 
powder  in  a  bore  hole  for  the 
purpose  of  introducing  a  fuse 
or  train. 

Prill,  a  solid  piece  of  pure  metal 
from  an  assay.  To  "prill" 
a  sample  is  to  add  some  richer 
substance  to  it  so  as  to  obtain 
a  false  return. 

Pulveriser,  a  machine  for  grind- 
ing ores  instead  of  stamping 
them  is  now  often  so  called. 

Punch  or  Punch  Prop,  a  timber 
support  for  the  roof  of  a  mine. 

Purser,  the  person  who  is  re- 
sponsible for  the  accounts 
and  pays  the  men  in  a  mine. 
He  is  both  treasurer  and 
secretary. 

Putter,  one  who  conveys  ore 
from  the  working  to  the 
horse  way,  or  the  bottom  of 
shaft. 

Pyritous,  containing  pyrites. 

Quartz,  a  very  abundant  hard 
mineral  substance. 

Quartzose,  containing  or  con- 
sisting chiefly  of  quartz. 

Racks,  a  kind  of  frames  for 
dressing  tin  ores. 

Reduction  of  Ores,  the  extrac- 
tion of  the  contained  metal. 

Riddle,  a  sieve. 

Riddling,  sifting. 

Rider,  a  mass  of  rock  dividing 
a  vein.  See  "Horse." 

Ringer,  a  crowbar. 

Rise,  to  work  upwards  towards 
the  surface. 

Roasting.     #ee  "Burning." 

Rod,  the  upright  beam  of  a 
man- engine. 

Roof,  the  part  of  a  mine  or  level 
above  the  miner's  head.  In 
Cornwall  called  the  "back  " 


142 


GLOSSARY. 


Houghs  or  Rows.  See  "  Crop- 
tin." 

Run,  when  the  parts  of  a  mine 
or  excavation  fall  together, 
they  are  said  to  "run. 

Run  of  a  Vein .  See  ' '  Direction. " 

Sampler,  the  person  who  takes 
the  samples  of  ores  for  assay- 
ing, or  determining  their 
value. 

Scraper,  an  instrument  for  ex- 
tracting the  dust  or  rubbish 
from  holes  while  boring. 

Serin,  a  small  vein.  Derby- 
shire term. 

Seam,  a  bed  of  coal  or  iron  ore 
is  often  so  called. 

Seat  or  Sole,  the  floor  or  bottom 
of  a  mine  or  level. 

Set,  to  set  or  make  an  agree- 
ment with  miners  for  the 
execution  of  any  piece  of 
work.  See  "Bargain." 

Sett,  the  tract  of  land  in  which 
a  mine  is  situated. 

Setting-day,  the  day  set  apart 
once  a  month  for  making  bar- 
gains with  miners  for  the 
future  working  of  a  mine. 

Shaft,  a  deep  pit.    All  the  deep 

'  pits  in  a  mine  sunk  down 
from  the  surface  are  called 
shafts. 

Shaft-pillar,  a  portion  of  ore 
left  unwrought  around  a 
shaft  for  the  sake  of  strength. 

Shake,  a  fissure  in  the  earth. 

Shake,  a  quarryman's  term  for 
a  crack  in  a  block  of  stone. 

Shift.     See  "Core." 

Shade,  to  trace  the  position  of 
a  lode  by  observing  the  scat- 
tered loose  stones  from  its 
upper  part  or  "back." 

Show,  a  pale  blue  tip  to  candle- 
flame  indicating  fire-damp. 


Shutting  or  Shooting,  blasting. 

Sink,  any  excavation  in  a  down- 
ward direction. 

Sinking,  digging  downwards. 

Skep.     See  "Skip." 

Skimpings,  the  upper  layer  of 
impure  tin  ore,  which  is 
scraped  off  from  that  which 
has  settled  in  a  kieve.  It  is 
taken  off  and  dressed  over 
again  by  itself. 

Skip,  a  kind  of  carriage  in  which 
ore  is  raised  from  the  bottom 
of  the  mine,  sometimes  called 
a  "skep." 

Slag,  a  waste  product  formed  in 
smelting  ores. 

Slate,  a  kind  of  rock  which 
splits  readily  into  thin  layers. 

Sled,  a  sledge  without  wheels. 
See  "  Corve." 

Slide.    See  "Fault." 

Slimes,  fine  mud  containing  par- 
ticles of  tin.  See  also  "  Crop- 
tin." 

Slipes,  flat  pieces  of  iron  for  the 
corves  to  slide  upon. 

Slitter.     £ee"Pick." 

Sludger,  an  instrument  for  re- 
moving the  mixture  of  dust 
and  water,  or  "  sludge,"  from 
bore  holes. 

Slyne.    See  "Joints.  " 

Smalls,  small  coal  or  ore. 

Smitham,  small  dust  of  lead  ore. 

Sollar,  a  small  platform  at  the 
foot  of  a  ladder  in  the  shaft. 

Sough,  an  adit. 

Spale,  a  fine.  For  absenting 
himself  from  the  mine  with- 
out leave,  or  for  breaking  any 
of  the  rules  of  a  mine,  a  man  is 
liable  to  be  fined  or  "spaled." 

Spall,  Spalling,  breaking  large 
stones  of  ore  to  a  smaller  size, 
so  as  more  readily  to  pick  out 
the  barren,  stony  parts. 


GLOSSARY. 


143 


Spar, "a  Cornish  miner's  name 
for  quartz.  A  Derbyshire 
name  for  fluor. 

Spathose  Iron  Ore,  Sparry  Iron 
Ore,  iron  spar,  or  carbonate 
of  iron. 

Spel,  a  change  or  turn.  Thus, 
if  several  men  have  to  do  a 
piece  of  heavy  work  upon 
which  all  cannot  work  at 
once,  they  change  about,  each 
taking  a  spel. 

Spreaders,  pieces  of  timber 
placed  across  a  shaft  which 
seems  likely  to  fall  in,  to 
serve  as  a  temporary  support 
until  it  can  be  properly  tim- 
bered. 

Stamping,  the  breaking  of  ores 
into  fine  particles,  in  order 
that  they  may  be  dressed  for 
sale. 

Stamps,  contrivances  for  stamp- 
ing ores. 

Stamps-head,  the  block  of  iron 
which  forms  the  lower  part  of 
the  stamps. 

Standard,  the  price  of  metallic 
copper  or  tin. 

Stem,  a  day's  work. 

Stemple,  a"strong  beam  placed 
in  a  slanting  position,  so  as 
to  support  the  walls  of  a 
lode. 

Stemples,  pieces  of  iron  o*r  wood 
fixed  into  the  sides  of  a  shaft 
to  serve  instead  of  ladders. 

Stickings,  narrow  veins  of  ore, 
also  capels. 

Stone-axe,  a  tool  used  in  dress- 
ing the  surface  of  blocks  of 
stone. 

Sto-w,  to  pack  away. 

Stowce,  a  windlass. 

Stowces,  pieces  of  wood  used  to 
indicate  possession  of  any 
part  of  a  mine. 


Stratified  Rocks,  rocks  occur- 
ring in  regular  beds  or  strata. 

Streamers,  persons  who  work 
in  streams  in  search  for  stream 
tin. 

Stream  Tin,  that  kind  of  tin  ore 
which  is  obtained  from  stream- 
works.  It  is  the  most  valu- 
able kind  of  ore,  and  yields 
the  purest  tin. 

Strik  or  Streek,  to  lower  any- 
thing down  a  shaft  by  means 
of  a  windlass. 

Strike,  the  direction  of  the  out- 
crop of  a  bed  of  rock  in  a  level 
country,  or  a  line  at  right 
angles  to  its  dip. 

Strings,  thin  vein  of  ore  in  con- 
nection with  a  lode. 

Stuff,  the  material  raised  from 
the  mine,  whether  ore  or 
deads. 

Stull,  timbers  placed  in  the 
backs  or  upper  parts  of  levels, 
and  covered  with  poles  or 
boards,  to  support  the  walls, 
or  rubbish  which  it  is  not 
desired  to  bring  to  surface. 

Sturt,  a  tribute  bargain  which 
turns  out  extraordinarily 
•well  for  the  miner  is  called 
a  sturt. 

Sump,  the  bottom  of  the  engine- 
shaft,  which  is  usually  sunk 
below  the  deepest  level,  so  as 
to  form  a  pit  in  which  the 
waters  may  collect  before 
being  pumped  up. 

Sumpmen,  men  who  assist  pit- 
men to  keep  the  sumps  clear. 

Sump-shaft,  the  engine-shaft. 

Swabstick,  an  instrument  for 
removing  dust  and  mud  from 
bore-holes. 

Swall,  a  cavern  or  opening  into 
which  water  falls,  and  is  lost 
sight  of. 


144 


GLOSSARY. 


Syenite,  a  hard  kind  of  granite 
containing  hornblende. 

Tackle,  the  ropes,  chains,  kib- 
bles, and  other  arrangements 
for  raising  ore,  etc.,  in  con- 
nection with  any  shaft. 

Tacklers,  small  chains  to  put 
round  loaded  corves  to  keep 
the  coal  or  ore  from  falling 
off. 

Tails,  the  roughest  of  the  refuse 
tin,  which  is  often  stamped 
over  again. 

Tamping,  the  filling  in  of  a  bore- 
hole above  the  gunpowder 
with  clay,  etc.,  so  as  to  secure 
a  more  effective  blast. 

Tamping,  the  material  used  in 
the  above  operation. 

Tamping  Arrow,  a  long  and  thin 
piece  of  metal  used  for  mak- 
ing a  communication  through 
the  tamping  of  a  bore-hole 
with  the  powder  at  the 
bottom. 

Tamping  Bar,  a  bar  used  in 
driving  in  the  tamping  mate- 
rial in  tamping  a  hole. 

Thill,  the  floor  of  a  mine. 

Threads.     See  "Strings." 

Thro-w.    See  "Fault." 

Tnrust,  the  falling  in  of  a  mine 
after  supports  are  removed. 

Thurst.     See  "Thrust." 

Ticketings,  the  weekly  meetings 
for  the  sale  of  ores. 

Tie.     See  "Tye." 

Tile  Ore,  a  valuable  ore  of  cop- 
per. A  variety  of  red  copper 
ore. 

Timbering,  the  fixing  of  timber 
in  a  mine  to  support  the  sides 
of  shafts,  or  the  walls  and 
roofs  of  levels  is  called  timber- 
ing. 

Timber-man,  one  whose  dutv  it 


is  to  see  to  the  timbering  of 
a  mine. 

Tinner,  tin  miner,  more  com- 
monly tin  streamer. 

Tinstone,  the  ordinary  ore  of 
tin,  often  called  cassiterite. 

loadstone,  a  name  used  in  the 
middle  and  north  of  England 
for  the  masses  of  basaltic  rock 
which  are  often  found  forced 
up  through  the  coal  measures. 

Tozing,  the  last  operation  in  tin- 
dressing.  The  nearly  clean 
ore  is  violently  stirred  up  in 
a  kieve  with  water,  and  then 
allowed  to  settle,  while  a 
continual  knocking  is  kept  up 
against  the  sides  of  the  kieve. 

Tramway,  Tram,  a  railway 
suited  for  the  passage  of 
waggon-loads  of  ore  or  coal. 

Trap,  a  general  term  often  ap- 
plied to  all  the  various  kinds 
of  greenstone  and  basalt. 

Tributer,  one  who  works  upon 
tribute. 

Trouble,  a  "fault." 

Trunk,  a  long,  narrow  pit  into 
which  the  slimes  are  directed, 
so  that  the  ore  may  subside. 

Tubbing,  the  lining  of  timber  or 
iron  which  is  often  applied  in 
order  to  secure  the  sides  of  a 
shaft. 

Tut- worker,  one  who  works  up  on 
tut-work. 

Tye,  a  long  narrow  channel 
(leading  directly  from  the 
stamps)  in  which  the  stamped 
tin  ore  is  often  partially 
dressed. 

Tying,  washing. 

Underlie,  the  amount  of  slope 
of  a  lode  or  vein,  measured 
from  the  perpendicular.  It 
is  the  same  as  the  "dip"  of 


GLOSSARY. 


145 


a  bed,  only  that  the  dip  is 
measured  from  the  horizontal. 

Unstratified  Rocks,  rocks  not 
occurring  in  regular  beds  or 
strata. 

Upcast,  the  ascending  air  cur- 
rent from  a  mine. 

Uphill.     See  "Bord." 

r 

Vamping,  the  debris  of  a  stope 
which  forms  a  hard  mass 
under  the  feet  of  the  miner. 

Vanning,  the  art  of  separating 
ores  from  veinstuff  by  wash- 
ing on  a  shovel. 

Vein,  a  lode. 

Veinstone  or  Veinstuff.  See 
"Gangue." 

Ventilation,  the  art  of  removing 
foul  or  spent  air,  and  of  sup- 
plying pure  and  fresh  air  in 
its  place. 

Viewer,  a  superintendent. 

Vugh,  a  cavity  in  a  rock.  A 
Cornish  term. 

Wall  of  a  Lode,  the  side  where 
it  comes  in  contact  with  the 
surrounding  country.  In  fig. 
3,  p.  27,  the  lode  underlies  to 
the  left;  the  upper  or  left 
side  a  a  is  called  the  hanging, 
and  the  lower  or  right  side 


b  b  the  foot  wall,  a  piece  of 

waste  land. 
Wastrel,  a  tract  of  waste  land, 

or  any  waste  material. 
Water-wheel,  a  wheel  made  to 

turn  by  a  stream  of  water. 
Wheal,   the  Cornish  name  for- 

a  mine,  often  and  more  pro- 
perly spelt  huel. 
Whin,  any  very  hard  stone. 
Whinstone,  trap. 
White  Tin,  metallic  tin. 
Whits,  tin  ore  partially  dressed. 
Winding  Engine,  an  engine  used 

for  drawing  up  ore. 
Windlass,  a  machine  used  for 

raising  weights. 
Winds  or  Winze,  a  shaft  which 

only  communicates  between 

two  or  several  levels,  but  does 

not  come  to  surface. 
Work,    the  ore  or  other  stuff 

which  is  raised  from  a  mine. 

Thus,  miners  speak  of  rich 

work  and  poor  work. 

Yellow  Ore,  the  miners'  name 
for  copper  pyrites  or  chalco- 
pyrite,  the  most  common  ore 
of  copper. 

Yokings.     See  "Stowces." 
Yokes  (yucks),  used  in  lowering 
heavy  pumps. 


18c 


INDEX. 


ADIT,  84,  87. 

Age  of  mineral  deposits,  17,  18. 

Air,  composition  of,  114. 

Air-pump,  101. 

Air-sollar,  116. 

Aitch -piece,  90. 

Alluvial  mining,  52. 

Amalgamation,  113. 

Angles! te,  21. 

Antimonite,  22. 

Argentite,  21. 

Arrastre,  113. 

Arsenic,  111.1 

Assaying.  112. 

Augurs,  64. 

BALANCE-BOB,  93. 
Balance,  water,  84. 
Balshag,  92. 
Barytes,  22. 
Basalt,  23. 
Bearing  of  lodes,  28. 

„         cross  courses,  28. 
Bed  mining,  46,  47. 
Bed-plank,  74. 
Bismuth,  21. 
Bit,  64. 

Black  copper  ore,  21. 
Black  jack,  22. 
Black  oxide  of  iron,  21. 
Blasting,  57. 
Blende,  22. 
Blue  copper  ore,  21. 
Boilers,  loa 
Bord,  51. 
Borer,  57,  64. 
Boring,  49. 
Bottom-nozzle,  93. 
Brake-staff,  88. 
Branches,  27. 
Brittle  silver  ore,  21. 
Brown  oxide  of  iron,  21. 
Buddling,  109. 
Burning,  110. 

CAGE,  76. 
Calamine,  22. 
Calcining,  110. 
Calcite,  22. 
Candles,  121. 
Cann,  22. 
Capel,  27. 
Caphead,  117. 


Carbona,  24. 

Carbonate  of  iron,  21. 

lead,  21. 

lime,  22. 

zinc,  21. 

Carbonic  acid,  114. 
Carboniferous,  18. 
Cassiterite,  21.   , 
Gaunter,  27.     ,*J 
Cerussite,  21.    --j 
Chalcocite,  21.  *  ^ 
Chalcopyrite,  21. 
Champion  lode,  27. 
Chalybite,  21. 
Chain,  78. 
Chessylite,  21. 
Chemistry,  14. 
China-clay,  57. 
Chlorite,  22.    . 
Cinnabar,  21. 
Clack,  89. 
Clay  slate,  23. 
Classification  of  rocks,  15. 
Coal,  22. 
Coal  gas,  122. 
Costening,  29,  30. 
Cobbing,  107.  . 
Cockle,  22. 
Collar  launder,  89 
Composition  of  air,  114. 
„  rocks,  20. 

Compound  engines,  102. 
Condenser,  101. 
Construction  of  horse  whim,  81. 

„  poppet  heads,  82. 

„  tackle,  79. 

Copper  ores,  21,  111. 

„  produce  of,  106. 

Cornish  boilers,  103. 

,,      engines,  85,  96. 
Cost  of  adit  levels,  87. 
„      climbing,  71. 
„      cover  and  filler  roads,  75. 
-n      crushing  ore,  107. 

driving  levels,  41,  52,  54. 

gads,  62. 

horse-whim,  82. 

kibbles,  74. 

lighting  mines,  121,  123. 

man  engine,  70. 

picks,  61. 

poppet  heads,  82. 

raising  ore,  76,  84. 


INDEX. 


147 


Cost  of  removing  burden,  56,  67. 

„  „       pillars,  52. 

,,      shovels,  62. 

„      sinking  shafts,  41. 

„      skip-roads,  75. 

„      stoping,  44,  54. 

„      stripping,  54. 

„      tackle,  81. 

„      timber  in  Cornwall,  42. 

,,      timbering,  42. 

,,      tram -waggons,  72. 

,,      trial  borings,  47,  48. 

,,      wheel-barrows,  72. 

„      whim-kibbles,  74. 

,,      whipsey-derry,  81. 
Cover  and  filler  roads,  75. 
Covered  binding,  37,  38. 
Cretaceous,  17. 
Cross-course,  27. 
Crashing,  107. 
Cylinder,  97. 

DAO,  65. 

Dark  red  silver  ore,  21. 
Dead  work,  34,  65. 
Devonian  rocks,  18. 
Diamond  boring,  50. 
Dimensions  of  shafts,  35. 
Diorite,  28. 

Direct  acting  pumps,  105. 
Dolomite,  22,  23. 
Door-piece,  90. 
Drainage  of  mines,  87. 
Drawing  lift,  89. 
Drawing  ore,  71. 
Dredge  ore,  110. 
Dressing  of  ores,  106. 
Drills,  64. 

EDUCTION  PIPE,  98. 

„        valve,  see  "Exhaust  valve.' 
Elvan,  19,  23. 
End,  44. 
Engines,  compound,  103. 

„        Cornish,  85,  97. 

„        duty  of,  102. 

„        horizontal,  85,  86. 

„        pumping,  97. 

„        water,  83. 

winding,  85,  86. 
Eocene  rocks,  17. 
Equilibrium  pipe,  98. 
„  valve,  98. 

Erubescite,  55. 
Exhaust  valve,  98. 

FAULT,  47. 

Felspar,  23. 

Felsyte,  23. 

First  use  of  gunpowder,  10. 

Flange-pins,  92. 


Flats,  24. 
Flookan,  27. 
Floors,  24. 
Flues,  104. 
Fluor,  22. 
Foot- wall,  27. 

GAD,  64. 
Galena,  21. 

Gas  in  mines,  122,  123. 
Gash-veins,  24. 
Gneiss,  23. 
Gold,  21,  113. 
Gossan,  27-29. 
Granite,  23. 
Great  adit,  87. 
Green  copper  ore,  21. 
Greenstone,  23. 
Grey  antimony  ore,  22. 
Grey  ore,  21. 
Guides,  27,  75. 
Gunnies,  44. 
Gjpsum,  22,  23. 

HAMMERS,  61. 
Hanging  wall,  27. 
Hatchet,  65. 
Heat  of  mines,  120. 
Heaves,  30,  33. 
Heavy  spar,  22\ 
Hematite,  21. 
Horizontal  engine,  85,  86. 
Hornblende,  22. 
Horn  silver,  21. 
Horse,  27. 

Horse-gin  or  whim,  81. 
Hydraulic  mining,  56. 
H-piece,  90, 

IGNEOUS  ROCKS,  16. 
Inclined  shaft,  36. 
Indicator,  86. 
Indications  of  mineral  deposits, 

„         of  heaves,  33.    - 
Intersections,  31. 
Iron  ores,  21, 106. 
Iron  shafts,  21. 

JACK,  22. 
Jigging,  112. 
Jumper,  64. 

KERARQYRITE,  21. 
Kibble,  73,  74. 
Kieve,  110. 
Killas,  17,  23. 

LADDERS,  66. 
Lamps,  121. 

Lancashire  boilers,  103. 
Launder,  76. 


148 


INDEX. 


Laurentian  rocks,  18. 
Lead  glance,  21. 

Pricker,  65. 
Productive  work,  34-43. 

Lead  ores,  21,  112. 

Proustite,  21. 

„         produce  of,  106. 
Levels,  39,  40. 

Pumping  engine,  86-96. 
Pumps,  88. 

„      timbering  of,  40,  42,  54. 
Liassic  rocks,  18. 

Purple  copper  ore,  21. 
Pyrargyrite,  21. 

Lighting  of  workings,  121. 
Light  red  silver  ore,  21. 
Limestone,  23. 

Pyrites,  22. 
Pyrdusite,  22. 
Pyromorphite,  21. 

Limonite,  21. 

Lode,  24. 

QUARTZ,  22. 

Lodes,  hearings  of,  28. 

Quartzyte,  23. 

„      underlie  of,  26. 

„      width  of,  26. 

RAKE  VEINS,  24. 

„      intersections  of,  31, 

Red  copper  ore,  21. 

Riffles,  113. 

MAGNETIC  IRON  ORE,  21. 

Rocks,  21. 

Main  rod,  92. 

Rows  or  "roughs,"  111. 

Malachite,  21. 

Man-engine,  69. 

SAFETY  CATCH,  67. 

Manganese  ores,  22. 

Sampling,  112. 

,,             produce  of,  106. 

Schorl,  22. 

Mercury  ores,  21. 

„      rock,  23. 

Metallic  minerals,  21. 

Serpentine,  22,  23. 

Metamorphic  rocks,  16. 

Sets  and  laths,  38,  39. 

Methods  of  raising  ore,  73 

Set-oifs,  92. 

Mica,  22. 

Shaft,  brace  of,  37. 

„     schist,  23. 

dimensions  of,  35. 

Minerals,  20. 

downright,  36. 

Mineralogy,  13. 

inclined,  36. 

Mining,  mechanics,  10. 
,,       geology,  12. 

iron,  53. 
partings,  67. 

Miocene  rocks,  17. 

position  of,  50 

railways,  75, 

NATIVE  METALS,  21. 

securing,  37. 

Natural  ventilation,  119 

timbering,  37. 

Nature  of  air,  114. 

Shell,  22. 

Shode,  28,  29. 

OOLITIC  ROCKS,  18. 

Shoots  of  ore,  24,  35. 

Open  works,  55, 

Shots,  10. 

Ore-dressing,  106. 

Shovels,  61. 

„    crushing,  107-111. 

Silurian  rocks,  18. 

„    stamping,  107. 

Silver  ores,  21,  113. 

Skip,  75. 

PARALLEL  MOTION,  98. 

Skip  roads,  75. 

Patch  works,  56. 

Slides,  33. 

Peach,  22. 

Slimes,  109. 

Penthouse  (Pentus),  66. 

Slips,  47,  see  "Faults." 

Permian  rocks,  18. 

Snore,  89. 

Phosphate  of  lead,  21. 

Spall,  106. 

Pick,  59. 

Spar,  22. 

Pillars,  size  of,  51. 

Springs,  30. 

„      removing,  52. 

Stains,  30. 

Pipe-veins,  24. 
Piston,  98. 

Stamps,  107. 
Starting  the  engine,  99. 

Platinum,  21. 

Steam  engines,  85,  96. 

Pliocene  rocks,  17. 

„      valve,  99. 

Plunger  lift,  90. 

„      jet,  117. 

Plutonic  rocks,  19. 

Stemples,  10. 

Post-tertiary  rocks,  17. 

Stock  work,  25,  26. 

INDEX. 


149 


Sloping,  43. 
Stratified  rocks,  16. 
Strength  of  chains,  73. 

„          hemp  ropes.  78. 

•wire  rope,  78. 
Striking  deals,  66. 
Stripping,  54. 
Stall,  44. 
Suction  pump,  88. 
Sulphate  of  lime,  22. 
Sulphur,  111. 
Swabstick,  58,  65. 
Syenite,  23. 

TACKLE,  73,  79. 
Tahonas,  113. 
Tarn  ping  bar,  65. 
Throw,  47. 
Timbering,  37. 
Tin  ore,  21,  106. 

„       produce  of,  56,  57,  106. 
Tin  stream  works,  52,  56. 
Tools,  59. 
Top  nozzle,  98. 
Tozing,  110. 
Tram  plates,  73. 

,,      waggon,  72. 
Tramway,  72. 
Trap,  23. 

Trevithick's  boiler,  103. 
Trial  borings,  47. 

,,  cost  of,  49. 

Trias,  18. 
Tributer,  45. 
Trompe,  117. 
Trouble,  47. 
Tungsten  ores,  21. 
Tut-work,  40. 

UNSTRATIFIED  ROCKS,  16. 


^ALVE  GEAR,  101. 
fanning,  11. 
Ventilation,  115, 119. 
Volcanic  rocks,  19. 

IVALL  PLATES,  38. 
"Water  balance,  84. 
machine,  83. 

quantities  raised,  104, 105. 
trompe,  117. 
wheels,  83,  95. 
Wedge,  64. 
Weight  of  chain,  78. 

„          Cornish  engine,  102. 
„         hemp  rope,  78. 

iron  wire  rope,  78. 
main  beam,  102. 
main  rods,  93. 
,,         pumping  engine,  102. 
rails,  73. 

steel  wire  rope,  78. 
„         tools,  61. 
,,         tram  waggon,  72. 

water  raised    in  Cornwall, 

105. 

„         -whim-kibUes,  7 
Wheel- barrow,  9,  72. 
Whim,  81. 
Whinstone,  23. 
Windbore,  89. 
Wjndsail,  117. 
Windlass,  9,  73,  80. 
Winze,  44. 
Working  barrel,  89. 
Working  the  engine,  100. 
Wolfram,  22. 

YELLOW  ORE,  21. 
ZINC  ORE,  21. 


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